How long will the London heatwave last? Lengthy hot spell to lift temperatures above 30C

Heat health alert for London is extended to next weekend as temperatures to rise
Megan Howe, News Reporter|Michael Howie, Senior News Editor
4 days ago

Another summer heatwave is expected to start today with forecasters predicting highs above 30C for London next week.

It follows record-breaking temperatures at the end of June, with heat and humidity playing havoc with public services as Londoners sweltered and flocked to lidos across the city.

Temperatures reached 37.7C in Norfolk on June 26, making it the hottest June day on record.

Now, the mercury is on the rise once again, with temperatures expected to hit 28C in London on Saturday - before rising to 32C on Monday.

Forecasters at the Met Office are predicting a growing area of high pressure will sweep in, although this spell of hot weather may be a little easier to cope with than the last.

People queue for a river taxi in Westminster, central London, during the heatwave (Yui Mok/PA)
People queue for a river taxi in Westminster, central London, during the heatwave
PA Wire

They say temperatures will steadily climb day by day and, while conditions are unlikely to match the intensity of late June, heatwave thresholds are likely to be reached in parts of southern and eastern England.

At the time of publication (6.30am on Saturday morning), the Met Office is predicting seven straight days of temperatures between 28C and 32C.

A heatwave is defined in London as at least three consecutive days where the maximum temperature reaches 28C.

A yellow heat health alert has been issued by the UK Health Security Agency for London for between noon on Saturday and 8pm on Saturday, July 11.

It warns of a heightened risk to health, particularly for vulnerable people, due to the expected heat.

However, with high pressure positioned further west, westerly winds should help keep temperatures below the extremes recorded in June while also bringing lower humidity levels.

That means many southern and central areas are likely to enjoy a predominantly dry week, with temperatures climbing into the high 20s and potentially topping 30C in parts of the South East.

June equalled the historic heatwave of 1976, as a red weather warning was issued for parts of England and Wales.

And the string of record-breaking temperatures in June came hot on the heels of May's heatwave, when the mercury climbed to 35.1C in Kew, London, smashing the previous May record of 32.8C, which had stood since 1922.

<p>LONDON, ENGLAND - MAY 26: A man takes a photograph from Westminster Bridge on May 26, 2026 in London, England. The UK has recoded the hottest May temperature on record with a blistering 34.8°C registered at Kew Gardens. Overnight temperatures also reached a record-breaking 21.3°C, marking the country's first-ever spring "tropical night." This extreme heatwave has triggered Amber Heat-Health Alerts across central and southern England. (Photo by Carl Court/Getty Images)</p>
A man takes a photograph from Westminster Bridge on May 26
Getty

Scientists warned the severity of last month’s heatwave – which affected much of mainland Europe as well as the UK – would have been virtually impossible 50 years ago.

An analysis by the World Weather Attribution group found a similar heatwave occurring in the climate of 1976 would be 3.5C cooler and would not have seen the same daytime peaks and overnight temperatures as in 2026.

Professor Stephen Belcher, Met Office chief scientist, said: “Human induced climate change has made events like this more likely and more intense.

“To see temperatures like this in the UK in June is sobering.

“Events like this bring home the implications of climate change, with very high temperatures and humidity bringing significant health implications from heat stress, as well as impacts to a range of sectors such as transport, energy and water supply.”