London heatwave: Capital could sizzle in 33C this weekend on UK's 'hottest ever May day'

London could swelter in its hottest-ever May weather over the Spring bank holiday weekend, with temperatures tipped to rise as high as 33C.

The Met Office is forecasting an official heatwave over the capital with four consecutive days of temperatures at 28C or higher starting on Saturday.

The hot weather is expected to peak on Sunday with the Met Office predicting a likely high of 32C.

Forecaster Tom Morgan said there was a 40% chance temperatures could climb to 33C in parts of southern England on Sunday, which would make it the warmest May day on record.

The highest May temperature ever recorded in the UK is 32.8C, in Camden Square, London, on May 22, 1922.

Any temperature above 29.4C will be the warmest May temperature recorded in the UK since 2012, the Met Office said.

Temperatures in the UK are expected to exceed those forecast in Mediterranean hotspots including Mykonos, Rhodes and Santorini over the weekend.

It's been a cool May - so far🌡️

That's set to change quite dramatically over the coming days. A prolonged period of very warm weather is now increasingly likely. Temperatures will rise to well above average for May with the hottest spots possibly exceeding 30 Celsius📈 pic.twitter.com/4PkfcG2n6r

— Met Office (@metoffice) May 20, 2026

As the heat builds, the UK Health Security Agency (UKHSA) has issued heat health alerts covering much of the Midlands, eastern England and south-east England.

The agency warned of “minor impacts” across health and social care services, including increased demand from vulnerable people, hotter indoor environments and a higher risk of water-related incidents.

Mr Morgan said: “This is a prolonged period of high temperatures.”

A UK heatwave is officially recorded when an area experiences at least three consecutive days with temperatures meeting or exceeding the region’s heatwave threshold.

The warmest day recorded in the UK so far this year was 26.6C at Kew Gardens in London in April.

Deputy chief forecaster Greg Wolverson said: “A very warm period of weather will develop through the weekend and into next week for much of the UK.

“High pressure will be in charge of the UK’s weather over the bank holiday weekend and this should bring fine and settled conditions to most areas.

“The exception will be parts of northwestern Scotland, where it will be cooler and cloudier with some rain at times. There is also a small risk of some thunder in the south late on Friday into Saturday.”