UK braces for persistent hot weather with peak of 27C as potential heatwave takes shape

26 April 2025, 13:44

The UK is bracing for several days of hot weather next week, with temperatures expected to reach as high as 27C.

Forecasters predict conditions will become increasingly warm from Monday - but whether any parts of the country will see an official heatwave remains to be seen.

Wednesday and Thursday look set to be the warmest days of the week, with 27C expected "quite widely", most likely in London, Berkshire, Hampshire, and possibly Kent and East Anglia.

Grahame Madge, a Met Office spokesperson, said: "This would always have been a naturally warm spell.

"However, with the footprint of climate change, you can expect it to add a degree or so to the values that we would have expected.

"So, it's likely that the temperatures for this event will be slightly higher.

"At the moment, it looks as though we're probably not going to see heatwave conditions met."

According to the Met Office, the definition of a heatwave is three consecutive days of temperatures exceeding the "heatwave threshold", which varies across the country.

Read More: Heatwave alert as temperatures could reach up to 10C above average during London Marathon

The threshold is 25C for most of the UK, with slightly higher numbers for the south and east, and rising to 28C in London.

Mr Madge said any chance of a heatwave depends on the progress of a cold front which is expected to move south.

"Now, as that front moves south, it will be pulling in cooler air behind it. Not cold air, but cooler air," he said.

"That will clip temperatures. So, there's a lot of emphasis on when this cold front will start to move and how much progress it will make during Thursday."

Dry and sunny conditions are expected for the thousands taking part in the TCS London Marathon on Sunday, with highs of 22C forecast for the capital.

The warmer weather comes after a difficult period for fire services across the country which battled wildfires earlier in month following historically low rainfall in March.

It looks like Sunday's London Marathon runners will try to complete the 26.2 mile course.

Some 56,000 people are expected to tackle the route in what is the 45th edition of the event

It could enter the record books as the largest marathon in the world if the number of finishers surpasses the 55,646 who completed the New York Marathon in November.

The TCS Mini London Marathon will also take place on Saturday, with about 17,000 children due to run, jog, walk, or wheel one mile (1.6 kilometres).

A warm spell of weather is expected to start on Sunday before forecasts become a little bit sketchy as there is potential for a lot of cloud to come in from either the north or south.

Mr Partridge added: "Typically for people that are running the marathon, that (warm weather) kicks in on the wrong day.

"For those guys, they probably would have rather run the day before when it would be be three or four degrees cooler."