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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