An early look ahead at what the UK summer may have in store

After a remarkably warm and dry spring, with record-breaking May temperatures, summer 2026 could continue this warm trend in the UK. Current trends indeed favour above-average temperatures throughout the season. However, rainfall patterns appear more varied.

June looks to start unsettled and cooler than late May, with chances of rain, but later in the month there is a signal for high pressure to return - bringing drier and warmer conditions. The signal is more muted thereafter for July, but it will likely be warm, sometimes hot, but changeable. August could be the hottest month of the summer and the driest month of the summer too.

The latest seasonal forecasts strengthen the signal for El Nino development in the next few months. The US NOAA’s ENSO: Recent Evolution, Current Status and Predictions update on 26th May states:

El Niño is likely to emerge soon (82% chance in May-July 2026) and continue through Northern Hemisphere winter 2026-27 (96% chance in December 2026 – February 2027).

As a result, seasonal models will likely show patterns that are consistent with typical El Nino teleconnections through the summer.

For Europe, the latest multi-model C3S seasonal forecast issued on 10 May showed that summer will be influenced by a relatively weak atmospheric pressure pattern with anomalously-high sea-level pressure in northern regions. The individual weather model seasonal predictions are more mixed, but do together show the anomalous high pressure signal in northern parts of Europe.

Seasonal temperature is forecast to be above average in all regions, with the most confident signal over southeastern parts of the continent. As is usually the case, signal for precipitation are much weaker than for temperature for June-August.

For June, we usually look at the ECMWF subseasonal forecasts, which are updated daily, these give a much more reliable indication for the outlook a month ahead, than using a seasonal forecast, which is issued earlier in the month. 

A look at the current subseasonal weeklies from ECMWF shows low pressure in charge bringing unsettled conditions during the first half of the month, but high pressure returns during the second half and perhaps a lingering influence into early July, but tending to migrate to the north of the UK, which may mean less settled eventually for the south.

Beyond a month, we use a combination of seasonal model forecasts and also composite charts of pressure patterns for summer months in years which had similar ENSO status, i.e. this summer having a developing strong El Nino, such as 1997.

A list of key years where El Niño conditions initiated or actively formed during the summer months includes:

• 2023: A well-documented, strong El Niño developed during the summer and peaked in late 2023. June was the hottest in recorded history, July was actually cooler than June and unsettled too, August was unsettled with low pressure dominating, there were two named-storms too.
• 2015: Warming accelerated in the tropical Pacific during the summer months, triggering one of the strongest events on record. June was dry and sunny with average temperatures, July unsettled and cool after a very hot 1st day of the month, August was generally cool and unsettled, very wet in the south.
• 1997: Summer development led into the exceptionally powerful "super El Niño" of 1997–1998. June that year was the wettest of the century, ‘June Monsoon’ and also cool, July was warm but changeable, August was the 2nd hottest of the 20th century (after 1995).
• 1991: A strong El Niño developed during the summer and extended into the following year. June cool and wet, July warm but changeable, August warm and dry.
• 1987: Conditions began escalating during the summer, leading to a mature event that winter. Cool, dull and wet June, dry, fine & warm July until mid-month, then downhill thereafter through much of August - often cool, cloudy and wet but with a brief hot spell mid-August.
• 1982: A rapid warming phase established itself by summer, culminating in a historically strong event. June that year was the wettest that century before 1997, July warm and dry, August around average temperatures.

As you can see above, quite a mix bag of weather comparing each month of each year, though June in 1982, 1987, 1991 and 1997 were all cool and unsettled. 

A 500 hPa height anomaly composite of the above years for July and August is shown below and will be used in the summer forecast. A composite for June won’t be used, as the sub-seasonal models will be more a reliable indicator a month ahead.

July

August

For July the composite shows higher 500 hPa height anomaly towards Iceland and over southern Europe, lower off SW Europe. This would infer a warm pattern but with no signal for lower or higher heights over the UK, potential for unsettled weather at times towards the southwest. For August, high 500 hPa height anomaly evident over southern UK and eastward, lower heights towards Iceland, a very warm and dry pattern.

Early thoughts are that June will likely be unsettled during the first half, with average to maybe slightly below temperatures and above average rainfall, but tending to turn drier and warmer during the second half. July a mixed month with drier more settled spells but also a few unsettled spells too, but warmer than average. August a hot and dry month, particularly in the first half, but unsettled conditions possible but shorter than dry and settled periods, most of any rain in the west.

A full summer forecast will be issued during the first week of June.