Welcome to my 15th annual UK/Europe summer forecast. As always, when compiling this forecast for the upcoming June-August period there are multiple factors which are taken into consideration. They include the past winter pattern, type of spring just observed as well as the current ENSO state, global and regional sea surface temperature anomalies etc.
Quick Summer 2024 Recap
Following a warm, wet spring, summer 2024 was fairly mixed and turned out slightly cooler than normal for the UK with rainfall slightly below the 1991-2020 average with 94%. Coolest since 2015 but slightly warmer and drier for England and Wales and the 2nd half of the season was more settled and warmer than the first half.
The synoptic says it all with deep trough extending from Greenland to Scandinavia including northern UK with slightly above average heights France and Iberia which led to cooler, wetter N, warmer, drier S.
2m temp anomaly for June-August 2024
Away from UK, France, Low Countries and Scandinavia, the rest of Europe was warmer than average.
Summer is likely the most difficult season to predict due to less contrasts and forcing as well as tele-connection indicators. This is worsened by a more uniform ‘warmer-than-normal’ ocean temperature’. Since 2015, the Atlantic has become warmer with peak heat around 2022/23.
While we can use past years as a guide, they become less useful with a more uniform warmer land, ocean and atmosphere but there are aspects to consider.
- How wet or dry, warm or cold was spring?
- Where are the warm/less warm or cool waters positioned in the Atlantic?
- Tropical cyclone activity mid/late summer which can create a ripple effect on the pressure pattern!
- Effects of ENSO and transition to a warm or cold phase.
Spring 2025, Opposite of 2024?
Spring rainfall & associated pattern can be important when it comes to summer temperature and pressure.
Spring 2025 will go down as one of the warmest and driest for central and northwest Europe including both UK and Ireland despite an unsettled end to May and the season.
While this, like last spring will go down as one of the warmest, it is opposite on the rainfall department thanks to an opposite 500mb pattern.
500mb geopotential heights 1 March through 14 May, 2024
Spring 2024 was the UK’s 6th wettest.
This spring has seen high pressure dominate in an unusually persistent fashion.
1 March through 8 May 2025
March-April rainfall
Note the difference in terms of soil moisture in the below graphics. We were in good shape last April while the drought area is growing in size and intensity this year.
Late April 2024
Late April 2025
This is ‘likely’ to create a warmer-than-normal feedback widely I suspect.
High soil moisture can lead to lower daytime temperature (but potentially higher night temps) as a result of some of the sun’s energy converted to evaporation of moisture being drawn from wet ground into the air which leads to limited warming of the air.
Less moisture in the ground means most incoming energy goes into directly heating the air, leading to warmer temperatures.
I don’t believe it’s a coincidence that we had a cooler first half to summer followed by warmer 2nd half last year as the pattern became less wet and ground dried some following the wet spring.
Notable Dry Springs since 2000
2003
2007
2011
2015
2017
2018
2020
2022 (UK’s last drought summer)
UK Top 10 Driest Springs
UK Top 10 Warmest Springs & Following Summer
10. 1952 (mixed summer)
9. 1992 (Warm dry start, cool, wet end)
8. 1999 (Mixed with warm spells)
7. 2020 (Very mixed with hot, cool, wet, stormy spells similar to 2015)
6. 2022 (hot, dry with UK’s first 40C)
5. 2014 (Distinct contrasts of warm July, cool August)
4. 2007 (very wet & cool)
3. 2011 (cool, wet)
2. 2017 (warmer, drier June/July, Cooler, wetter August. Coolest/wettest NW)
- 2024 (Often cool and wet)
The above list of notable dry and warm springs in some aspects doesn’t give much of an indicator for the upcoming season. Following springs similar to 2025, there have been very dry and warm as well as cool and wet summers.
Wet To Dry… ENSO Connection?
While ENSO has less influence on Europe compared to the Americas, Africa and Australasia, there are still impacts.
There is a reasonably clear wet followed by dry period for NW Europe over the past 18 months.
El Nino began during summer 2023 which was warm and WET, the following winter (23-24) was also wet followed by a wet spring 2024.
Then came La Nina which began summer into autumn 2024. A slightly below average summer for rainfall in 2024 was followed by a drier 2024-25 winter followed by very dry spring 2025.
Winter 2023-24 was WET and this continued into spring 2024 (above) perhaps leading to the cool summer of 2024 with rain just slightly below average. The 2024-25 (La Nina) winter just gone was drier than normal followed by dry spring 2025.
An ENSO Neutral Summer
A fairly weak La Nina has now transitioned to neutral which means summer will be neither El Nino nor La Nina and so no real signal from the Pacific.
That being said, One could argue that the drier signal may linger through at least the first half of summer 2025.
NORTH ATLANTIC: Record Warm North east, Cooler E Tropical!
As of May 2025, the North Atlantic remains warm in the east, cooler central/west.
When comparing to May last year, there’s less extreme warmth through the eastern tropical and subtropical belt due to unusually persistent low pressure causing upwelling. The greatest heat is stored around the UK and Ireland thanks to persistent high pressure.
This SSTA configuration could support additional high pressure feedback when combining dry soils, however one cannot rule out an eventual flip to lower heights and if so, greater heavy rainfall and flood events.
Other years with similar Atlantic SST profile (warm around UK, cooler Cent N Atl) combined with neutral ENSO.
2020 (warmer around Azores)
2017 (cooler Cent N Atl)
2005 & 2002 have some slight similarity.
The problem with pre 2010 and particularly 2000, waters both in the Atlantic and globally were considerably cooler though 2025 is arguably less warm in Atlantic and globally compared to 2023 and 2024.
Relevance Of An Early Final Stratospheric Warming?
The primary relevance to an unusually early warming may be the unusual persistence of high pressure which resulted in one of the driest springs for UK, Ireland and perhaps much of Europe.
It’s difficult to say whether the early final warming has any relevance into summer but there could be evidence supporting a drought summer for parts of Europe, especially France to Germany.
The Role of the Madden Julian Oscillation
The MJO is a two-part wave of enhanced and suppressed convection over the tropics (fueled by the warm tropical waters of the Indian and Pacific Oceans). While one region (hemisphere) experiences the active branch with enhanced thunderstorm activity (lower pressure), another experiences sinking (high pressure). The importance and influence of the MJO can have global impacts and this teleconnection is often used in my forecasts.
From my understanding of how the MJO works with it’s large-scale rising and sinking branches of the circulation and heat release into the higher latitudes, one can think of it as ‘less influence’ or potentially higher pressure for Europe when the active phase is over the Indian Ocean (phase 2-3) and Maritime Continent (phase 4-5) with sinking over the Americas/Atlantic/Africa. This tends to lead to suppressed tropical cyclone activity in the Atlantic but when the active branch of the MJO moves east from Indian to Pacific Oceans, the rising cell drifts into the Americas and Atlantic (phase 6-7-8) creating a more favourable environment for tropical cyclones and more forcing towards Europe in the form of eastward advancing rossby waves & breaking.
When it comes to the MJO beyond 1-2 weeks, it becomes harder to predict as is the case with forecasting in general but certain modes often lead to certain pattern types and when the rising branch of the MJO is present over the Atlantic, there’s more forcing and interaction between equator and pole on our side of the planet. The CFSv2 isn’t particularly enthusiastic that the MJO is going to spend much time away from the Indian Ocean/Maritime continent through the upcoming summer.
Type of Atlantic Hurricane Season could prove important
NOAA predicts above-normal 2025 Atlantic hurricane season
While a busy Atlantic at face value may not mean a whole lot to the European pattern, the type of pressure pattern (Bermuda-Azores high) strength and position could be, especially if we see for example more storms or hurricanes lifting north towards the mid latitudes.
A warmer west MDR, Caribbean and Gulf of Mexico could support more favourability for storm development and strengthening but the east of the MDR is a lot cooler than this time last year. ENSO is less influence on whether it’s a busier or quieter season but neutral ENSO’s and warmer Atlantic overall leans to a slightly busier overall season but WHERE the mid-Atlantic ridge core (Bermuda or Azores) could mean a lot to the type of mid and late summer pattern we see. It becomes more dynamic and complex.
If we happen to see a stronger Azores rather than Bermuda cell, systems that develop could turn north before reaching the Caribbean/North America. This can help boost high pressure or reinforce lower pressure over the northeast Atlantic. European heatwaves often happen late summer as tropical heat pumps high pressure downstream over Europe. Equally, they can reinforce low pressure and a cool, wet pattern.
Multi-Model
Multi model
Thoughts
The below graphic is more overall visual on the June-August period.
In my opinion, when looking at past ‘dry springs’ there’s no definitive evidence supporting either hot, dry or cool, wet. It’s a bit of a guess. However, combing record warm SSTA’s particularly just west of Europe, dry ground widely, neutral ENSO and likely slightly busier than normal Atlantic hurricane season, it points to a highly volatile, varied and potentially extreme summer of weather swings. 2015 and 2020 comes to mind.
The unusually warm surrounding waters (compared to normal) and dry ground could support some notable heat surges/Spanish plumes but also a recipe for serious flood events, especially in the form of thunderstorm activity. A couple of lengthy ‘hot & dry spells’ is expected along with equally low pressure dominance. The lean towards low NW, high SE on the whole with fluctuation of both.
There’s past evidence suggesting a drought summer for a large swathe of continental Europe possibly extending into England with that early stratospheric warming as shown in the above tweet from World Climate Service
With cooler eastern tropical Atlantic, my hunch is the Azores high could be stronger than normal through the first half of summer with frequent northward extension in June. At the peak of this summer’s heat, I think 38-40, locally 42C is possible for France including north, 34-36C SE England with 28-30C widely England, Wales and Low Countries, possibly 30-31C Scottish Borders.
MONTH BY MONTH BREAKDOWN
June
Potentially driest of the 3 month period with a lengthy spell of high pressure, above average temperatures, below average rainfall for much western and central Europe including UK and Ireland. The month could commence unsettled but a change to more settled heading towards June 10th with peak of the dry, warm or hot spell between 10-20th before a return to lower pressure late month.
Near avg rain Scot, NI, ROI, avg to below avg Eng and Wales.
Max temps: 31-33C England, 28-30C Wales, 28-30C Scot, 27-28C NI, ROI
July
Another somewhat mixed month with back and forth pressure swings containing decent summer heat. With a lot of ‘warmer than average’ fuel in the surrounding seas, thunderstorms could be lively with frequent lightning, gusty wind and hail storms with flash flooding an issue especially to end a week to 10-day ‘hot spell’. Cooler, wetter and windier for Scotland and Northern Ireland but not without some warm to hot days.
Avg to slightly above avg rain much of UK and Ireland, Wettest NW.
Max temps: 32-34C England/Wales, 27-29, possibly 30C Scot, NI, ROI.
August
Depending upon the MJO position/strength and tropical activity in the Atlantic, we could see everything in August with major heat surges and or a lengthy hot, dry spell due to re-curving tropical systems reinforcing the high over Europe but also some lows generating unseasonably cool, wet and windy days. Timing of high vs low impossible to say but highly variable month is possible.
Avg to below avg rainfall Eng, Wales, S ROI, avg to above Scot, NI, N ROI.
Max temps: 34-36C SE Eng & near continent, 29C Scot, 28C NI & ROI.
Key Points
Warmer, Drier spells compared to last year
Chance of hot & dry periods in each of the 3 summer months.
Potentially turning more unsettled through mid to late season
Long hot, dry summer likely for much of central and Mediterranean Europe, Wetter Balkans & SE.
Coolest, wettest Iceland, NW UK & Ireland, drier further south and east.
The Verdict
Warmer-Than-Normal for much of Europe (Except NW). Wetter-Than-Normal Iceland, Scotland, Northern Ireland, NW Rep of Ireland, S Norway, Sweden & SE Europe, Drier-Than-Normal MUCH of Central & Western Europe Including much of England, Wales, SE Rep of Ireland…
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