Seasonal Forecasts

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  Winter Weather Forecast 2025/26

  Welcome to my winter weather forecast 2025/26 for Reading and the surrounding areas, though also can probably apply more widely.

  Starting with the usual caveat that seasonal forecasting is experimental, some of this will be wrong – a successful forecast would see more right than wrong overall.

  Plus events happen that shift weather patterns, such as the recent technical sudden stratospheric warming, which initially increased the chance of cold weather patterns, but as it played out, it seems it has enhanced the usual westerly Atlantic-driven pattern instead. This forecast, at least for December/January is significantly different from what I was expecting a couple of weeks ago.

  And thanks to Margaret for the photograph.

  Background Signals

  La Niña is in evidence though weak – this tends to mean colder flows are more likely in late autumn/early winter (as we had in mid/late November) westerly flows more likely in late winter.

  On the flip side, the Quasi-Bienniel Oscilation is in easterly mode, which reduces the chance of westerly flows.

  The SSW event has been what is known as a reflective event, and the primary effect of this is to strengthen westerly flows – so this will likely impact over the next few weeks.

  The Madden Julien Osciliation is currently in a phase which may lead to colder weather patterns in late December, but possibly the SSW overrides this.

  The stratospheric polar vortex is on the weak side, despite strengthening after the SSW – and my guess is that it won’t be so strong this year, which could lead to a lessening of westerly flows.

  Overall, one has to conclude that the background signals are rather conflicting this season.

  December

  The first half of December looks fairly unsettled, wind and rain some days, brighter on others though some showers possible. Temperatures often around average, sometimes mild.

  Around, or just after mid-December, high pressure may develop over or close to the UK, allowing for some drier weather, perhaps colder – overnight fog/frost possible. Cloudy skies more likely than sunny skies during the day.

  However, this is quite uncertain – and weather fronts probably would occasionally push through bringing some, but not a huge amount of rain.

  Suggestions that it becomes more broadly unsettled and milder by the end of the month.

  Overall I expect above-average rainfall, above-average temperatures, around or slightly-below average sunshine amounts.

  Confidence level of 70%, though lower for the second half of December.

  January

  More likely, January starts on the unsettled side with wind and rain at times – temperatures broadly on the mild side, though some short colder spells of north-westerly winds very possible.

  My guess is that around mid-month, perhaps a little earlier, we start to see high pressure to the east blocking progress of the weather systems. So it becomes often dry, often cloudy – perhaps overnight fog, possibly some overnight frost. Temperatures generally around average though some chilly weather at times.

  Perhaps more unsettled towards the end of the month as low pressure systems try to break down the block.

  Overall I expect slightly above-average rainfall, slightly above-average temperatures and slightly-below average sunshine amounts.

  Confidence level of around 50% – too many conflicting background signals to be really happy with this, there certainly is potential that it could be wetter for the whole month.

  February

  Low confidence for February though a fairly mixed start is perhaps the more likely outcome, with high pressure further north-east – not impossible there could be some colder weather from this set-up.

  After that, more likely high pressure regains control, though in what position is uncertain – so expect drier weather, hopefully more sunshine, but possibly on the cold side at times.

  Overall I expect slightly below-average rainfall, around average temperatures and around or maybe slightly-above average sunshine amounts.

  Confidence level of 20% – I’m wary both of La Niña seasons involved unsettled Februrys so it could be much wetter than normal – but also the weaker stratospheric vortex could be disrupted by another SSW, which could be more likely to provide cold/wintry weather.

  February really could be anything.

  Summary And Spring Thoughts

  Quite a hard forecast this season, especially for January and February – both months could easily be very wrong. I will update in the usual forecasts when things change.

  Very early to be thinking about spring, but I’d currently suggest March and April more likely to see some colder weather at times on current weather patterns. No strong signals on rainfall amounts this far ahead, but broadly around or slightly-below average would be my guess. Maybe time to plan that spring holiday!

  In summary, wetter earlier in winter, somewhat drier and colder in late winter though becoming highly uncertain.

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• 

  Autumn Weather Forecast

  Hello and welcome to my autumn weather forecast, aimed at Reading/Berkshire area but will be general enough to apply to most of south/central England.

  First up, the usual caveats – forecasting further than 5 days ahead is generally difficult, so forecasting for a season is very much experimental and can only be talked about in general terms.

  Some of this forecast will be wrong. Hopefully more will be right than wrong – that’s my general aim.

  That said, both my spring and summer forecasts have gone broadly very well, I suggested summer might be “one for the ages”, and I feel you could describe it as so – it was the hottest on record, with above-average sunshine and below-average rainfall.

  Alas, the autumn forecast looks trickier.

  Also, thanks to Amanda for the photograph. I had some stunning photographs sent in, but I didn’t want to use anything with too much sunshine in…for reasons you’ll soon read about!

  Background Signals

  Background signals tend to not have too much use in autumn, but I’ll cover them briefly.

  ENSO is currently neutral, though it looks like we may go into La Niña as autumn goes on, which would tend to increase the chance of westerly/north-westerly flows (some suggestions we may go into a significant El Niño next year, but not sure how reliable this is).

  Sea surface temperatures remain well above normal around the UK, so that suggests temperatures are more likely to be above normal – any colder weather from the north would likely be diluted.

  The hurricane season is the wildcard – prior to Hurricane Erin’s development, I was expecting a drier and warmer start to autumn, which has clearly been blown out of the water. It really was a game-changing system. Might another major hurricane change our weather patterns again? Who knows.

  September

  September starts unsettled – a brief dry and warm spell for the first weekend, then back to unsettled with spells of wind and rain for the next week, a chance of a named storm.

  Around mid-month, there’s a fairly good chance of high pressure trying to build across from the south-west, so generally drier, sunnier and warmer for a time in the second half of the month, though probably it won’t last too long – with the end of the month more likely to be unsettled, with the potential for notably strong winds/heavy rain.

  This does assume no major hurricane developing towards USA and changing our patterns.

  Overall I expect somewhat above-average temperatures, around average sunshine amounts and somewhat above-average rainfall.

  Confidence level of 60%.

  October

  October more likely starts on the unsettled side, with further spells of wind and rain, though this likely trends further east – which means into week two (give or take) less rain, but probably quite cloudy and breezy, with winds more likely from the north-west so a cooler direction.

  Low confidence, but high pressure to our south may have more influence in the second half of the month, so a drier spell though I’m not currently expecting it to be especially sunny or warm – that would depend on positioning of high pressure.

  Overall I expect around average temperatures, somewhat below-average sunshine amounts and somewhat above-average rainfall.

  Confidence level of 50%.

  November

  Currently I expect high pressure to have more influence in November, though probably positioned to our south-west or west, which tends to mean cloudy affairs in late autumn.

  So broadly a fairly cloudy month, some sunny days at times, some weather fronts at times will likely bring some rain/wind – those more likely in the first half of the month.

  Perhaps a greater chance than normal of colder north-westerly or northerly flows later in the month, if La Niña develops, which would at least mean sunnier weather – some overnight frosts possible too.

  Overall I expect slightly above-average temperatures (though perhaps cooler than average by day, milder by night – due to the cloud), below-average sunshine amounts and below-average rainfall.

  Confidence level of 50%.

  Summary And Early Winter Thoughts

  So a pretty mixed autumn seems more likely currently – drier towards the end, wetter towards the beginning.

  Confidence levels are lower than they were for my summer forecast – there are some conflicting signals in the long range models I use, and not really much to go on in terms of background signals.

  Current thoughts for winter are for dry and mild weather in December, more mixed later in winter, with the best chance of cold/snow being in February. But of course, this will likely change…it is sooooo far away.

  Happy autumn!

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• 

  Summer Weather Forecast 2025

  Welcome to my summer weather forecast 2025 for Reading & Berkshire, though more or less it would apply to much of England, should you be reading from further away.

  I’ll start with the usual caveat in that seasonal forecasting is impossible to get fully correct, a broad brush approach is the best we can do at the moment – and even then, meteorological events will change it.

  Hopefully more is right than wrong, that is my aim.

  My spring forecast was a pretty good guide, I was concerned that the very late sudden stratospheric warming event would cause some cold spells, but they didn’t transpire – otherwise there was lots of blocking highs to our north, plenty of sunshine, often warm – in fact record-breaking sunshine and warmth for the whole season.

  Also a quick thank you to Helen for the photograph – a charity donation will be sent when you let me know which. And also a thank you to those still sending them for the normal forecasts – they would be more boring without them.

  Background Signals

  Always less to go on in terms of background signals in summer.

  The late sudden stratospheric warming (or very early final warming of the stratospheric vortex, which it is probably classed as) does tend to marry up with drier and hotter than normal summers following.

  Well above-average sea surface temperatures should increase temperatures over the UK when we have high pressure, though may help to increase the jetstream strength when it is over us, due to the temperature contrast.

  Likewise the dry ground due to the lack of rain since February, will increase temperatures when it is sunny, and likely also reduce cloud amounts.

  Neither El Niño or La Niña are in play at the moment.

  And that is all I can think of. Onto the expectations.

  June

  June starts somewhat unsettled, a couple of fine days but more days will see at least some showers or rain – breezy/windy at times too, and cooler than normal.

  From week 2 it should warm up, still the chance of some showers on some days, but also a chance of some short very warm/hot spells too.

  High pressure should build more broadly from around mid-month to bring much more in the way of dry, warm and sunny days – probably quite hot some days, some cloudy starts possible though depending on wind directions.

  Perhaps a greater chance of showers at the very end of the month.

  Overall I expect above-average temperatures, somewhat above-average sunshine, and rainfall amounts slightly below-average – unless you get a notable downpour.

  Confidence level around 75%.

  July

  Fairly weak signals for July, though there is a fairly consistent but weak suggestion for high pressure to be close to the UK – positioning will be key, as always.

  To start the month, there is a greater chance than normal of some heavy showers/thunderstorms, but also some very warm/hot sunshine too.

  My semi-educated guess is that it will settle down more broadly for much of the rest of the month, with high pressure in control, and plenty of very warm/hot sunshine.

  Temperatures and the chances of thundery outbreaks will depend on the positioning of high pressure, there is some suggestion this could be close to our east which could put us in a loop of short hot/very hot spells followed by significant thundery breakdowns – but this is very low confidence this far out. There are other suggestions that high pressure is more likely positioned over the UK, or even slightly to the north which would reduce thundery outbreak chances, and keep things more normal (still very warm/hot) in terms of temperatures.

  Overall I expect above-average temperatures, above-average sunshine – rainfall amounts could be anything compared to average, depending on if you get some particularly heavy downpours on the showery days.

  Confidence level around 70%.

  August

  Less confidence for August, which should be no surprise as it is two months away (and normally the start of hurricane season which can cause changes in weather patterns for us) – however there remain signals for high pressure to be close to the UK.

  So my assumption is that there will more dry, sunny and very warm/hot weather for much of the month – though how hot will depend on where high pressure is positioned.

  Certainly a chance of some afternoon downpours developing on some days – I’d suggest later in the month more likely, though if high pressure is to our east, then there is a chance of going into a loop of short hot/very hot spells followed by thundery breakdowns.

  Overall I expect above-average temperatures, above-average sunshine amounts, and rainfall – well, less days of rain than normal, but amounts will depend on whether you get some notable downpours.

  Confidence level around 60%.

  Summery And Early Autumn Thoughts

  So, I’m suggesting a sunnier and hotter summer is more likely than not. To use one of those modern phrases, it could be a summer for the ages.

  If we find out in 3 month’s time that it was the hottest and/or sunniest summer on record, or close to, then I would not be surprised.

  However, the last time I stuck my neck out and predicted such a summer, it didn’t happen…so as always, take it with a teapot of salt.

  There’s no particular compelling signals for autumn, early suggestions for September seem fairly mixed, hints of a drier than normal October/November.

  Have a great summer! I think I’ll save my holiday time off (and holiday money) for later in the year.

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• 

  Spring Weather Forecast 2025

  Welcome to the Spring weather forecast 2025, aimed at Reading & Berkshire though probably applicable to most of the south of England, as I talk quite broad brush.

  I shall start with the usual caveat – seasonal forecasting can only be experimental, background signals can give an idea of what to expect, but notable events can override such signals.

  It looks like we are about to have a sudden stratospheric warming event, which is annoying timing, both for the accuracy of this forecast and for the prospects of good spring weather.

  This does mean that I’m less confident than normal – I’d rather be doing this forecast in two weeks time, and I may well do an updated version if the sudden stratospheric warming event happens (likely) and it upturns current expectations.

  In any case, no seasonal forecast from any forecaster will be completely accurate, except if they get exceptionally lucky. My winter forecast was alright – both January and February were wetter than I expected, but high pressure was in control for much of February as I expected, just in a slightly different place. December’s forecast was pretty good. I wouldn’t give myself especially high marks.

  Also I’d like to thank everyone that contributes, both in terms of comments on the Facebook posts and especially the photographs that are sent to me to use…the forecasts look much more boring without them.

  And for this forecast, thanks to Donna for the cover photograph – a small donation to the charity of your choice will be made shortly.

  Background Signals

  Background signals tend to mean less in spring/summer, though the one overriding factor is the likely sudden stratospheric warming event.

  Such events often (but not always) lead to high pressure blocks in positions that favour cold weather spreading down from the Arctic, or from Russia – so northerly or easterly winds.

  Whilst a northerly flow will always be cooler/colder than normal at any time of year, easterly winds from around mid-April onwards can be warmer than normal, depending on the exact air source, and how much North Sea cloud is involved.

  Effects from a sudden stratospheric warming (SWW) event tend to take 2-6 weeks to filter down into the troposphere (our level of the atmosphere).

  Until the event has happened, and still it is possible that it is just a notable warming of the stratosphere and not an SSW, we can only talk in chances of something happening.

  The other background signals include a weak La Niña and the QBO being in westerly phase, which should increase the chances of westerly flows. That said, these were also in affect during the winter, and we had reduced westerly flows compared to normal.

  Conclusion? No idea.

  March

  Well let’s start with the bit I know – March will start sunny with overnight frost and/or fog, and temperatures will recover to a little above average. Something more showery likely for a time for the second week – mild or quite warm at first, possibly colder later.

  Uncertainty increases notably for the second half. Something changeable broadly looks the theme, though with high pressure close by more often than not. Said high pressure more likely in milder positions, though brief cold snaps will remain possible, in the mix. Overnight frosts still possible. Some showers and occasional rain but overall probably more dry and sunny days, than showery days.

  Overall I expect above-average temperatures, somewhat above-average sunshine and somewhat below-average rainfall.

  Confidence level around 50% – pretty low compared to what I can normally feel.

  April

  Confidence really drops off a cliff now, due to the probable sudden stratospheric warming event, and the unknown outcomes – though outcomes more likely to favour cold flows than normal.

  I was very confident of high pressure being in control for April until recently, but one effect of an SSW event can be for the Arctic air to go flooding south to our west, over the Atlantic, which then blows up large areas of low pressure – we saw this last winter where SSW events led to something milder and wetter.

  But I’m going to stick to the more likely outcome, which is colder and drier weather with high pressure either to our north/north-west or west – allowing colder flows from the north or east for the first half of April.

  Variable amounts of sunshine and cloud from day to day, some showers likely – some sleet/snow would be possible. Colder than normal conditions more likely, but brief quite warm spells could be mixed in too. Overnight frosts still possible.

  I’d assume high pressure to continue to be fairly close by for the latter half of April, again some changeable conditions, some showers possible some days, though temperatures more likely to be average or above-average.

  Overall I expect around average temperatures, slightly above-average sunshine and slightly below-average rainfall.

  Confidence level just 20%. Damn that sudden stratospheric warming event.

  May

  By this point the effects of the SSW event (assuming it happened and assuming it was impactful) lessen. Should high pressure be to our north, the resulting easterly winds would be warm by this point – though should it be to our west, northerly flows still chilly.

  My best guess is that high pressure will be to our north to allow easterly flows, so often warm and sunny, though not always, for the start of May. Cloud spilling in from the North Sea overnight and leading to cloudy mornings – or possibly cool and cloudy days, is possible, in such a set-up.

  As the month goes on, heavy showers will tend to increase in prominence across the south of England, with low pressure tending to be close by to our south, over France. Potential for some decent thunderstorms (or indecent if you don’t care for them). Likely still warm/very warm with sunny spells.

  Overall I expect above-average temperatures, slightly above-average sunshine amounts and an average number of days of rain – rainfall totals could be anything, depending on how heavy any downpours are.

  Confidence level of 40%.

  Summary And Early Summer Thoughts

  Yikes…lots of uncertainty. May holds the most promise for those looking out for sunshine and warmth, though I do expect all 3 months to be sunnier than normal. Anything outstanding wet looks unlikely, though who knows what the effect of the SSW will be – all I can talk about is more likely outcomes for now.

  I wish the SSW event happened two weeks earlier, or I did my forecast two weeks later. Alas. Maybe I’ll do an updated version in two weeks but I doubt I’ll have time.

  Early summer thoughts are for a fairly hot first half/two-thirds of summer, though I’d still expect some heavy showers at times – early signals for August are looking notably wet. But that is a very, very, very long way away.

  And that is your Spring Weather Forecast 2025. Thoughts?!

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• 

  Winter Weather Forecast 2024/25

  Welcome to the winter weather forecast 2024/25 for Reading & Berkshire.

  Firstly the usual caveats – seasonal forecasting is difficult, no seasonal forecast will ever be 100% correct, as it is bound to events on a local and global scale.

  Seasonal forecasting is done mostly on a global level, and also thought of in monthly terms – for example, the background signals and long-range models could suggest higher than normal pressure is likely one month, but that wouldn’t stop one week or more being under low pressure, and wet.

  So you should always expect any seasonal forecast as a rough guide at best, and remember that I’m not a professional – just an amateur forecaster with a half-decent grip on what models are suggesting, and a decent writing ability.

  My autumn forecast was…alright…I picked some things out correctly, for example the greater chance of northerly flows than normal in November, but then I also picked out a wet start to November, and it was dry.

  Also a massive thanks to those who sent photographs in, and more so to those who do on a regular basis.

  Thanks to Clare who’s photograph I’ve chosen – a small charity donation will be sent as a thank you, please let me know to whom.

  Background Signals

  Winter always has more impactful background signals than any other season, but that never is the whole story – events do and will deviate from this.

  The Quasi-Biennial Oscillation is currently in westerly phase, which increases the chance of westerly winds, and hence milder, wetter conditions.

  La Niña, though not the strongest, does tend to increase the chance of northerly flows in autumn and early winter (as we have already seen).

  Sea surface temperatures around most of the UK, and especially to the west, are warmer than normal – so this will mean temperatures more likely to be higher than normal. However, to our north, sea surface temperatures are colder than normal – so northerly flows may have more impact in terms of cold than normal.

  The Indian Ocean Dipole is forecast negative for the start of winter, which can increase the chances of colder northerly flows.

  Finally, the Madden Julien Oscillation, which is only helpful (questionably so in my view) over the more medium-term, currently is forecasted to end up in phases which favour cold weather later in December.

  A sudden stratospheric warming event (SSW) cannot be discounted, which is where the stratosphere (the atmospheric layer above our troposphere) suddenly warms, which can break apart the polar vortex and cause cold weather to flood down in our direction – the Beast From The East in 2018 being the classic example.

  However, we had 3 such events last winter, a once in 250 years occurence – the first two arguably gave us much milder and wetter conditions, as the cold air from the Arctic, if I remember correctly, flooded south but to our west – and hitting the (relatively) warm Atlantic ocean caused large areas of low pressure – and the mild/wet conditions. And also caused the latter part of my winter forecast to fail!

  And the third happened in March, too late for wintry weather but then caused a cooler than normal spring.

  I’ve read arguments that La Niña combined with a westerly QBO increases the chance of an SSW occurring over winter…which is what we have. But not sure what to make of that.

  So quite a lot of different background signals, but definitely some patterns including increased chances of northerly flows in early winter – as such it is time to start the forecast.

  December

  December looks a very variable month, especially to start. It should settle down after the first week, with temperatures around normal or a little below, though some showers possible in the easterly flow. Frost/fog will be possible.

  After mid-month, something more changeable looks more likely with further heavy rain and strong winds at times – chances of more named storms, though temperatures most of the time above average – short colder snaps still possible.

  Towards Christmas and into the New Year period, colder northerly flows become more possible, though westerly flows could still dominate. Expect changeable conditions, wind and rain at times, some sunnier and colder days too. Again, quite a mix seems most likely, though perhaps veering towards dry more than wet.

  Overall I expect above average rainfall, around or slightly below-average sunshine, around average temperatures.

  Confidence level 80%.

  January

  January again looks a fairly mixed month. The start of the month has greater chances of drier and colder weather, before becoming unsettled once more. Northerly flows very possible, named storms very possible.

  In the second half of the month, something milder and changeable seems more likely – some rain at times, but also some dry spells, if perhaps cloudy and dry.

  Overall I expect around average rainfall, slightly below-average sunshine, and slightly above-average temperatures.

  Confidence level 60%.

  February

  Suggestions for February see higher than normal pressure over Europe, so something milder and drier than normal seems the more likely general outcome for the first half of the month – though some weather fronts will likely get through to bring some rain, albeit more limited amounts.

  More likely it stays mild or very mild in the latter half of February, with dry conditions more likely than wet.

  A sudden stratospheric warming event would increase the chance of cold and dry for February, considerably…but this is impossible to know at this stage.

  Overall I expect rainfall to be below average, sunshine around or slightly-above average, temperatures above average, though with some uncertainty towards the end.

  Confidence level 50%.

  Summary And Early Spring Thoughts

  So a pretty mixed winter seems more likely, though not quite as wet as it has been with high pressure playing more of a role than it has the last 18 months or so. Any cold spells more likely in the first 6 weeks of winter, and those from the north.

  Early signs for spring, assuming no sudden stratospheric warming, are for a much warmer and drier first half of spring. Oh do hurry up!

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• 

  Autumn 2024 Seasonal Weather Forecast

  And welcome to the rather delayed Autumn 2024 seasonal weather forecast for Reading & Berkshire – though it should broadly apply to much of southern England.

  Let’s start with the usual caveat – seasonal forecasting is experimental, some of this forecast will be wrong. It is my best attempt at using background signals, long-range models, current patterns, and, well, vibes to establish a more likely route through the next 3 months.

  Unexpected events can and do happen, and then throw off course the forecast.

  Thanks also to Paul for the stunning photograph – a charity donation will be made to MS Society. Thanks to everyone who sent them in, and also to those sending them in for the usual twice-weekly posts – the forecast would be a lot more boring without them!

  Background Signals

  We are probably transitioning back into La Niña conditions, which would increase the chance of cooler north-westerly flows later in autumn.

  The remnants of hurricanes can change our weather patterns when they recurve into the Atlantic, which adds uncertainly for September and to a lesser extent, October.

  However the intertropical convergence zone has been further north than usual, which is thought to be hindering tropical storm development. I have no idea if this will continue.

  Other than that, nothing really stands out as a background signal.

  September

  Well, September did start warm and unsettled, then went much cooler. That’s obviously not a forecast as I’m writing this on 12th September!

  Warmer weather will quickly re-establish itself, with high pressure likely to build close to the north – allowing a warm easterly to develop. Sunshine amounts should be higher than normal, though some overnight low cloud feels likely on some days, which could take a while to clear.

  Likewise in the final third of the month, low pressure may well develop to our south over Europe, with a chance of showers/thunderstorms moving north towards us at times.

  Lower confidence by the end of the month, but something more unsettled and somewhat autumnal is more likely.

  Overall rainfall amounts somewhat higher than average, sunshine amounts around average, temperatures somewhat higher than average.

  Confidence level around 60%.

  October

  October looks likely to have quite a notable westerly flow. Possibly starting unsettled though more likely I think low pressure will become centred to the north of the UK, so we’ll tend to be dry much of the time in the south, relatively mild, sometimes sunny, perhaps even the odd warm day. Then occasional weather fronts bringing a bit of rain every 2/3/4 days – that kind of broad pattern. Windy at times.

  Later in October, the more likely outcome seems to be that low pressure will be tracking further south, so areas of rain more frequent, heavier and more persistent, windy also – but still there should be some dry days too.

  Overall rainfall amounts around average, sunshine amounts around average, temperatures slightly higher than average.

  Confidence level around 50%.

  November

  During November, I expect the jetstream to be pushed further south, bringing some wet and windy/very windy conditions at first in November, but also a chance of some colder weather in between areas of rain.

  In the latter half of November, more likely the jetstream is to our south and we see broadly drier, sunnier and colder weather – northerly (ish) flows more likely than normal, overnight frosts and perhaps wintry showers.

  Overall rainfall amounts around average, sunshine amounts around average and temperatures slightly below average.

  Confidence level around 50%.

  Summary And Early Winter Thoughts

  So a pretty mixed autumn – some wet spells but also some notably sunny periods too. I’m not foreseeing a constant washout of an autumn.

  I’ve probably rushed the research of this compared to normal, so I’m a bit less confident, plus background signals seem pretty weak, but it will do for now.

  Maybe in a few years, the AI models which are giving me increased confidence in the 7-10 day range, will be able to help with longer range forecasting…will be interesting!

  Early winter thoughts are for a drier than normal winter – temperatures very dependent on positioning of high pressure systems, but assuming La Niña does develop, then cold spells very possible in December, a milder trend more likely in January/February but cold snaps still possible…of course, it is winter.

  Full daily forecast tomorrow.

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• 

  Summer Weather Forecast 2024

  Summer has officially started, and it is time to issue my summer weather forecast 2024. There’s even a bit of sunshine today.

  Usual disclaimer first, seasonal forecasting is experimental, nobody can tell you exactly what the weather will do in 42 day’s time. All I can offer is a broad based solution, based on background signals, recent weather patterns, long range weather models and a bit of guestimation.

  Some of this will be right (well, hopefully!), some of it will be wrong. The aim is to get more broadly right than wrong – but one can have all the confidence one likes about the weather 3 months away, from strong background signals, weather models, etc – then an event happens that changes all that.

  February this year was the perfect example – almost all background signals pointed to it being colder and drier than normal, weather models pointed that way too, the Met Office expected it, and still talked about it in February turning cold and dry. Yet it was ridiculously wet and mild…probably caused by the sudden stratospheric warming event in January, which in themselves normally cause cold and dry conditions.

  My spring forecast had unusually low confidence behind it, and was pretty mixed in terms of success – arguably April/May turned out closer to the forecast than March. It was warmer and wetter than normal across all 3 months – I didn’t really pick that out, alas.

  So take this with as much a pinch of salt as you want.

  Also thanks to Debs for the photograph…had probably 10 that I wanted to use, so thanks to everyone that sent them in, but this is the closest to my forecast.

  Background Signals

  Background signals are less effectual in summer than winter, and there isn’t much to go on.

  El Niño is fading into neutral ENSO conditions for summer, which I think favours reasonable weather in the UK, though with limited impact. We may transition to La Niña in August, but again I wouldn’t expect it to have much bearing on our weather.

  North Atlantic sea surface temperatures remain well above normal, I think record levels – this will both increase heat when high pressure is in control, and rainfall intensity when low pressure is in control – especially if low pressure originates further south.

  It’s also expected to be a busier than normal hurricane season – these are wild card events which can change the course of our weather patterns.

  June

  June looks fairly mixed. There is a fairly strong signal for high pressure to both dominant to our west, and also low pressure to our north/north-east, so this would suggest north-westerly flows more likely than normal for June.

  The month starts fine and fairly warm. Towards the first weekend, it may become somewhat cooler and showery, though low certainty on this aspect. Probably not huge amounts of showers.

  From then we likely alternate between cooler, cloudier spells with some showers and perhaps spells of wind/rain, and somewhat warmer spells with some sunshine.

  During the latter third/quarter of June, a trend to something warmer but still with chances of showers – any showers heavier by this stage.

  Overall I expect around average temperatures or even slightly below (rare in our warming world, if so), slightly below-average sunshine, and around average rainfall.

  Confidence level 60%.

  July

  Fairly weak signals for July, but the beginning part of the month would be more likely to see further mixed conditions, some short hot/very hot spells mixed in, interspersed with heavy showers/thunderstorms on other days, and some fine warm/very warm days.

  The latter half more likely drier, temperatures generally very warm or hot – though some short unsettled spells likely too – the mixed theme likely continues.

  Overall I expect above average temperatures, around average sunshine, and slightly above average rainfall (though will depend on localised downpours…which will skew this).

  Confidence level 50%.

  August

  What signals there are do suggest higher than normal pressure for August – which if this comes to pass (if!) may make a change from many recent summers.

  Broadly still likely a mixture of conditions, many very warm/hot days, but also some wet/showery days as low pressure systems are triggered by the heat over Europe.

  Suggestions that the latter part of August is a bit more of a westerly flow, and generally more settled, less hot, with reasonable sunny spells and only occasional weather fronts.

  Overall I expect above average temperatures, slightly above average sunshine, and…well…rainfall totals could be anything depending if you catch a torrential downpour or two, so maybe days with rain falling is a better measure, and that to be below average.

  Confidence level 50%.

  Summary And Autumn

  So…not bad. A pretty mixed but hotter than normal summer would be the general headline. But as I mentioned, the signals are weak, and I’ve been less successful with seasonal forecasts in recent years than I used to be. As always, take any weather forecast more than 5 day’s out with a huge bucket of salt.

  Early suggestions for autumn are for it to be warmer, drier (!) and sunnier than normal, at least for September and October, with hot spells still probable.

  Feel free to share this Summer Weather Forecast 2024, and enjoy your summer!

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• 

  Spring Weather Forecast 2024

  Spring has started, but its still pretty cold. Welcome to my weather forecast for Spring 2024.

  First off, the usual caveat. Seasonal forecasting is difficult, if not impossible. It is mostly about studying background signals, previous year’s weather patterns, pattern matching and expectations of future background signals.

  Events scupper this, as does a lack of understanding as to how conflicting background signals may work against each other. It’s pretty much best guesses.

  This February was a great example. My forecast was for a colder and drier month than normal, based on background signals overwhelmingly pointing to this outcome being more likely, and also the chance of a sudden stratospheric warming being high, in my view.

  Except we had the wettest and warmest February on record. What happened? Well, I assume events – it is often difficult to correlate what signal/event caused weather conditions, though I suspect the sudden stratospheric warming event counted against this time – whilst many lead to cold weather, some actually lead to milder conditions, and this SSW event was unusual in that it reflected back into the stratosphere and powered the stratospheric vortex, and hence we went into wet and mild overdrive. At least, I think that is the cause.

  All of which is to say that some of this will be wrong, perhaps very wrong. But hopefully enough will be reasonably inline to make it valuable.

  For December and January, my winter forecast behaved reasonably well – had February gone to expectations then I would have been very happy! Also I think I outlined future conditions in my twice-weekly forecasts with good levels of accuracy, quite often the pattern for 1-2 weeks ahead was clearer than normal. And I did drop the idea for a cold/dry February (or at least it turning so) earlier than the professionals did. So I’m content with my ongoing forecasts, if not the seasonal.

  I am considering stopping doing these seasonal outlooks, because I question the value, especially when they go so off-course like February does. Feedback welcome – I’m not just looking for positive platitudes!

  Finally thanks to Sarah for the photograph – a small donation has been made to The Brooke, as a thank you.

  Background Signals

  There’s always less influence from background signals in spring.

  However, there is likely to be a third sudden stratospheric warming event in early March, or strong and early final warming of the stratospheric vortex – whatever it is classed as, this will increase the chance of easterly and/or northerly winds later in March, and into April – and also push the jetstream south.

  It’s slightly annoying that I’m doing the forecast now, as in another week or so, after this stratospheric warming event, things will be clearer. So there’s more uncertainty in this forecast than normal.

  El Niño should also increase the chance of cold and dry conditions, at least in March, though that was the case for February too and look what happened.

  Easterly phase of the quasi-biennial oscillation should reduce the strength of westerly winds, and increase the chances of easterly flows.

  Sea surface temperatures are likely to remain at record highs in the Atlantic, and my reading of this is that there will be more moisture in south-westerly flows, but also much more warmth potential to tap into – depending on if/when high pressure builds over Spain.

  March

  The sudden stratospheric warming event probably puts hopes for an early spring to bed, but not necessarily.

  Most likely, March starts on the cold side, veers mildish then colder, showery days tending to drier days. Through the mid-month period easterly (ish) winds seem likely at times, which should make it colder at times, but also rain and milder weather will be pushing up from the south-west too. Where they meet, snow is possible – but chances do reduce of battleground snow in March, especially down here. A small chance of snow – nothing more.

  Later in March, easterly or northerly winds are more likely, so conditions generally on the chilly side with overnight frost probable at times. Otherwise some sunshine, some light/moderate showers, perhaps wintry and some outright cloudy/chilly days. Occasionally, milder and wetter conditions will push up from the south-west.

  Quite a mix really – and it will depend on where exactly high pressure sets up to our north (assuming it does) – so an outright wet month is plausible instead, but also a dry and cold month is too. My forecast is for a mixture of the two, with quite a bit of fluctuation.

  Overall I expect temperatures to be slightly below-average, rainfall around average and sunshine slightly below-average.

  Confidence level around 40% – lower than normal, due to the expected sudden stratospheric warming event in early March.

  April

  Assuming the stratospheric warming event happens, and the outcome is blocking highs to our north, then I expect April to start fairly chilly with showers or rain at times, with northerly or north-easterly winds being more likely than normal. Overnight frosts still very possible.

  There is a weak signal for high pressure to build over Spain in the second half of April, perhaps slightly earlier, so I’m going with that, and suggesting that will increase the chance of warmth (finally!) in the second half of April. Unlikely to be an extended warm spell – likely mixed with some weather fronts bringing rain on a few days, some heavy showers on other days – but some warmer, sunny-ish days too.

  Overall I expect temperatures to be around average – though a contrast between below-average to start the month, above-average to end, rainfall slightly above-average and sunshine around average.

  Confidence level around 40% again.

  May

  Background signals really drop off here, and long-range models are conflicting with each other, so in a forecast with lower confidence than normal, I’m even lower on confidence for May.

  My best suggestion is for the warmer than normal end of April to continue into the beginning of May, with some very pleasant days – though also a few interruptions – some showers, some occasional weak weather fronts bringing more cloud and rain, with fresher air following.

  The latter part of May perhaps looks more unsettled for a time (possibly warm/humid still), though with a trend to much warmer and drier conditions by the end of the month.

  Confidence level of 20% – unusually low.

  Early summer thoughts and summary

  So a mixed spring looks more likely, and not an especially joy-filled spring – with some colder and wetter conditions early. Though with the proviso that uncertainty is much higher than normal.

  Early signals for summer do point to a drier and hotter summer being more likely than normal, particularly June.

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• 

  Winter Weather Forecast 2023/24

  Welcome to my weather forecast for winter 2023/24 for Reading & Berkshire, though it is broad scale enough to easily be applied to much of central/southern England.

  Firstly the usual caveat – seasonal forecasting is experimental, and I actually seem to be getting worse at it! Some of this will be wrong – there is nobody who can accurately predict a month of weather repeatedly, certainly nobody can do three months. If this is all right, then it is at least partly down to luck.

  But, we can still have a reasonable idea about the more likely outcomes, given background signals, especially in winter where background signals are always much stronger and more effectual on our weather.

  That said, events happen that shape the weather outside of the background signals – and this is where long-range forecasts tend to go wrong.

  Also thanks to Louise for the photograph. Yes, I am braving a snow photograph – though how could I resist the accomplices?

  Background Signals

  El Niño tends to mean milder and wetter conditions earlier in the winter, drier and colder later in the winter.

  We are in the easterly phase of the Quasi-Biennial Oscillation (QBO), which tends to mean the westerly flow is less strong – so high pressure and even easterly flows can be more likely (ie colder conditions).

  The wild card in winter is always the chance of a sudden stratospheric warming (SSW) event – and these seem to be more common in winters that have the combination of El Niño and an easterly QBO. SSW events can lead to events like 2018’s Beast From The East – many significant winter events in years gone by had an SSW 2-4 weeks beforehand – but it never guarantees anything cold, just significantly increases the chances.

  The sea surface temperatures in the Atlantic are in what is known as a tripole – warmer than normal to our north-west, cooler than normal to our west, warmer than normal to our south-west. This is thought to increase the chances of the jetstream tracking further south, and hence allowing colder air south – winters of 2009/10 and 2010/11 had such a pattern.

  These are all in favour of cold weather during winter, or at least parts of winter.

  However, we live in a warming climate – this year is likely the warmest on record so there is that to take into account.

  And the Indian Ocean Dipole is in a strong positive phase, which a fair few years back was thought to be the main driver of our mild winter, when it looked like the background signals were pointing towards cold. So there is some conflict in background signals, as there normally is.

  In the shorter term, the Madden-Julien Oscillation is pointing towards the chance of colder conditions towards the end of December.

  December

  After a cold and fairly dry start to the month, the Atlantic will take over and it will become unsettled, with rain and sometimes wind. Generally becoming milder, though the odd colder day possible. Around or just after mid-month, high pressure will likely try to establish itself, at least for a few days.

  Before Christmas, more likely we revert back to something changeable, with some milder days with rain, some drier and cooler days, though less confidence on this period. Towards the end of the month (perhaps in time for Christmas but more likely after), increased chances of cold weather spreading down from a more northerly context – snow and ice become possible, though it may well be fairly marginal with the jetstream not likely to especially calm down.

  Overall I expect above-average rainfall, slightly above-average temperatures, slightly below-average sunshine amounts.

  Confidence level of 75%.

  January

  January does look like a particularly unsettled month – probably on the cold side to begin, with chances of snow, though again quite possibly marginal with mild weather trying to regain control.

  It shouldn’t take too long for this to happen – and become generally mild with rain and wind, perhaps some named storms. It likely wouldn’t always be mild – some colder conditions will be plausible as low pressure systems clear with short spells of north-westerly or northerly winds, perhaps with wintry shower and overnight frosts. But generally the theme for January is unsettled and fairly mild.

  Suggestions that towards the end of the month, high pressure over the continent may become more influential – so drier, perhaps cold and frosty – though less sure on this.

  Overall I expect above-average rainfall, slightly above-average temperatures, slightly below-average sunshine amounts.

  Confidence level of 65%.

  February

  The signs point towards an SSW being a bit more likely than normal this winter, so I’m tentatively suggesting February as a cold month, but I’m also assuming that both an SSW happens, and it is favourable for cold conditions in the UK.

  Cold, with overnight frosts and snow showers at times, especially if we end up with an easterly flow, though often dry.

  However, if an SSW does not happen, I still think a fairly dry and fairly cold month is the more likely outcomes, with overnight frosts and fog possible.

  Overall I expect below-average rainfall, slightly below-average temperatures and slightly above-average sunshine amounts.

  Confidence level of 40%.

  In Summary…And Early Spring Thoughts

  In summary, I’m expecting an unsettled and often mild December and January, though with some potential for cold and wintry spells. February has higher chances of cold and snow, though nothing is certain in long-range forecasting.

  Early suggestions for spring, are of a colder than normal spring, at least to start.

  Enjoy! And roll on spring warmth so I can get back into the sunshine.

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• 

  Autumn Weather Forecast 2023

  Welcome to my autumn weather forecast for 2023.

  First thing to note, as always, is that seasonal forecasting remains experimental. Whilst my forecast for June was good, and for August was respectable – for July I predicted a hot month. Aha. Though at least I thought there would be some rain, albeit of a thundery variety rather than Atlantic systems.

  So, some of this forecast will be wrong – due to events, it is impossible to give accurate long-range forecasts, but you can give a general guide based on current weather patterns, background signals, etc.

  I’m not sure what went wrong in July – did I misread the models? Perhaps but so did every other forecaster who I take notice of, in that case. I know there were unusual plunges of cold air into North America late June, which fired up the jetstream – and then there was some really anomalously warm waters off the coast of North America, which likely gave low pressure systems their oomph this summer.

  That’s my working theory on what went wrong anyway.

  So whatever I say here, take with a huge pinch of salt.

  Thanks to Sarah for the superb photograph, and to all those that sent in – there were a few particularly excellent ones to choose from.

  Background Signals

  El Niño is still developing and is probably going to be a strong event. I’m not sure that it has too much effect on the UK weather patterns in autumn, perhaps a slightly increased chance of westerly flows later on.

  Sea surface temperatures are still warmer than normal around the UK, which increase the chance of warmer than normal temperatures over the UK.

  The Quasi-Biennial Oscillation is now in easterly mode – I’ve seen some people on weather forums blame that for our summer weather, but I’m not buying it. Though perhaps it can increase the chance of blocking highs or easterly flows during autumn.

  As always, hurricanes/tropical storms and their remnants can affect our weather and add extra uncertainty, especially in September.

  September

  Speaking of hurricanes, Franklin is the major cause of our hot start to September, pushing high pressure east and allowing us to tap into continental warmth/heat.

  So an increasingly hot and sunny start to September, very possible that the highest temperature of the year is recording during September, though I think we’ll stay short of the UK all-time September maximum – which is 35.6’C. Some warm nights too, though some early morning mist/fog/low cloud in places.

  Towards the middle third, there will be (small) chances of thundery showers before the heat gradually faces, and by around mid-month or just after, we should be in something more changeable – perhaps briefly unsettled.

  In the latter part of the month, probably some variation with some showers, but a return to warm and dry looks more likely overall. Bear in mind that hurricanes/tropical storms far to our west add uncertainty to this.

  Overall I expect well above-average temperatures, above-average sunshine, and below-average rainfall – unless you catch a particularly heavy downpour during mid-month.

  Confidence level of 85%.

  October

  Signals are weaker for October though there is a fairly notable signal for high pressure close to the east of the UK.

  A dry start may give way to a spell of more unsettled weather into the first half of October, perhaps some very heavy, showery rain at times, and quite windy. Likely mild and occasionally warm.

  In the latter half of October, it seems more likely that the high to our east will push west somewhat, meaning rain stays to our west most of the time, and it should generally be dry, mild with some overnight mist/fog.

  Overall I expect above-average temperatures, around average sunshine and around or slightly below-average rainfall.

  Confidence level of 60%. The main risk is that the high pressure block is further east and low pressure systems get stuck over the UK – bringing a wetter month than I expect.

  November

  November I think will more likely start dry with high pressure close by. Overnight frosts with some morning mist/fog patches possible. Some sunny days, some cloudy days, temperatures around normal for the time of year.

  During the latter part of November, the jetstream should pick up and we’ll have a more westerly flow – some rain at times from weather fronts though I suspect the bulk of the heavy rain and strong winds will be towards Scotland. Generally mild/very mild under such a set-up. Uncertain on cloud/sunshine amounts.

  Overall I expect slightly above-average temperatures, around average sunshine, below-average rainfall.

  Confidence level of 50%.

  Overall and Early Winter Thoughts:

  So drier and warmer than normal for autumn, is what I expect. We shall see!

  Early thoughts for winter are mostly for a mild and dry winter with a strong signal for higher than normal pressure over Europe.

  I wouldn’t preclude a cold spell, and there will be some rain at some point, but overall drier and milder than normal seems the most likely outcome – albeit it’s 3 months away!

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