When will the UK heatwave return and how long will it last?

Forecasters have said temperatures will reach as high as 36C as Britons head into the weekend. 
Crowds of holidaymakers and sunseekers flock to the packed beach at the seaside resort of Lyme Regis to soak up the sunshine
Celia McMahon / Alamy Live News
Charlie Duffield4 August 2020

Parts of the UK can expect scorchingly hot weather this week, with temperatures reaching 36C according to the latest forecasts.

Meanwhile in the rest of Europe, sweltering heat has led several cities in Italy to go on "red alert", with record temperatures in Spain.

The latest heatwave comes after temperatures reached 37.8C at Heathrow Airport at 2.41pm and 37.3C at Kew Gardens, in west London on Friday, making it the third hottest day recorded in the UK.

Met Office forecaster Bonnie Diamond said the hot weather will be part of a “warm spell across the UK” but the highest temperatures are expected to be “focused in the south-east of England”.

Here's what you need to know about the upcoming heatwave.

When will the UK heatwave return?

Following a "mixed" spell of weather at the start of the week, Met Office forecaster Bonnie Diamond said the hot weather will start from around Thursday.

These high temperatures are the result of southerly winds moving from Europe and high pressure patterns.

UK Heatwave: Hottest day of 2020 so far as mercury hits 31C

1/36

Ms Diamond said: “The pressure pattern is generally high so in combination with the southerly winds and high pressure we get settled, sunny and hot weather.”

She added: “At the minute, and with high confidence, we are expecting 34C to 36C by Friday and Saturday.”

Speaking to The Standard, Graham Madge from The Met Office explained: “For a heatwave to occur in the UK, there had to be temperatures of 25C or above for at least 3 days.

“That rises to 28C and above in London. The South East is always likely to be warmer, so there is a higher threshold.”

How long will the heatwave last?

Mr Madge said there is some uncertainty regarding how long the hot temperatures will last, but it will certainly be for at least the weekend at the moment.

Sunny spells and generally settled weather can be enjoyed across southern areas but heavy rain is on the way for Northern Ireland and Scotland on Tuesday.

Ms Diamond added things will then start to settle down from Wednesday, with warm weather developing across the UK.

“But it is going to turn hot across the south-east, where temperatures are going to be well into the 30s,” she said.

These high temperatures could trigger some thunderstorms on Friday and Saturday.

Deputy chief meteorologist David Oliver said: “High temperatures could trigger some thunderstorms across southern parts of the UK over the weekend, but for most there will be plenty of dry and sunny weather.

“At the moment there is some uncertainty as to how long the hot spell of weather will last.”

Will temperatures exceed the hottest day of the year so far?

PA

The highest UK temperature, 38.7C, was recorded in Cambridge University Botanic Garden on July 25 2019.

The second hottest day was a recorded at 38.5C in Faversham, Kent, on August 10 2003.

Tim Legg, of the Met Office’s National Climate Information Centre, said: “An area of low pressure in the Atlantic acted to draw warm air up from the continent, bringing a day of heat to much of the UK with a particular focus on the south-east.

“This made it the hottest day of the year so far by some margin and it also measures as the third hottest day on record in the UK.”

Friday’s hot temperatures came at the end of a cool month of cloud, rain and predominantly westerly winds across parts of the UK in July.

Temperatures were around 14.3C on average, which meant the UK as a whole was minus 0.8C below previous averages for the month, the Met Office said.