Will there be another heatwave in September? Here’s what we know

Environment
20 Aug 2026 • 9:45 PM MYT
The Independent
The Independent

The world’s most free-thinking newspaper

Will there be another heatwave in September? Here’s what we know

Heavy downpours and flash flooding were predicted for parts of the UK this week, before drier conditions return over the weekend.

The rain and cooler temperatures were welcomed after back-to-back heatwaves left the ground hard and dry with 70 per cent of England and Wales in drought.

Provisional Met Office data shows that the UK’s mean temperature for meteorological summer so far is currently at 16.48C – that is 1.88C above the 1991 to 2020 average temperature. England has recorded a mean summer temperature of 18.19C so far, 2.46C above average.

The remainder of August would need to be 1.41C below the summer average for England to equal its current warmest summer on record, also set in 2025.

The UK has just emerged from its fifth heatwave of the year (PA)

But will there be another dry and sunny spell this summer?

What does the long range forecast say?

Looking ahead, the Met Office’s long range weather forecast predicts that the changeable weather is likely to continue.

From early next week the south of England is forecast to see more unsettled weather as longer spells of rain spread north across many parts of the UK.

In the days before the start of September some heavy bursts and thunderstorms are likely.

“Thereafter, it will likely remain changeable through the rest of August and into early September, with rainfall amounts probably above average for the time of year,” according to the Met Office.

But warm and hot spells are still possible, although they will likely be short lived, with temperatures sitting near average.

There will be some drier and more settled spells before an unsettled start to autumn.

At the start of September the Met Office predicts all areas will probably see a mixture of showers and dry weather.

While the beginning of September will bring varying temperatures by mid-September, there may be an increase in the extent of drier, more settled weather, especially in the south and east, according to forecasters.

What records have been broken this summer?

The Met Office said last week temperatures had reached 37.6C at Charlwood in Surrey, while at Wisley temperatures had hit 37.2C, and Kew Gardens in London had recorded a temperature of 38.1C – the highest temperature recorded in the UK this year.

A further 10 weather stations were at or above 36C, the provisional figures from the Met Office showed.

England has recorded a mean summer temperature of 18.19C so far, 2.46C above average

It makes 2026 the first year on record to see three separate days where temperatures reached the 37C threshold, as well as the first year with four days at 36C or above.

Before 2026, the UK had recorded 37C or higher on only six occasions.

It also extends 2026’s record-breaking run of days above 35C.

For four months in a row temperatures hit 35C in the UK on at least one day in May, June, July and now August.

July was also the driest month since records began in 1836 in both England and Wales, southern England alone had its driest calendar month ever on record.

By 15 July this year the UK had already recorded more days above 30C than in the whole of 1976, which was known for its long-lasting heatwave.

Why is the UK experiencing more heatwaves?

Climate change is making extremes such as heat and drought more intense and more likely.

The UK's weather is becoming warmer and wetter, and adverse weather events - heatwaves, flooding, extreme cold - are growing more frequent and intense. The last decade has been warmer than any previous decade on record, and summers we once considered exceptional are becoming the norm.

The Met Office explains that the UK is experiencing higher maximum temperatures and longer warm spells in recent years. Warm spells have seen their average length more than double – increasing from 5.3 days in 1961-90 to over 13 days in the decade 2008-2017.

But the outlook could get worse. A study by the Met Office Hadley Centre suggests the current chance of seeing days reaching 40C or more is extremely low. However, by 2100 under a high emissions scenario the UK could see 40 C days every three to four years.

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