Temperatures climbed to 34.6C in Wisley, Surrey on Tuesday as a rare red extreme heat warning took effect across parts of England and Wales, forcing hundreds of schools to plan closures and the UK's largest train operator to warn passengers not to travel unless necessary.
The red warning, issued by the Met Office from 09:00 BST Wednesday until 21:00 Thursday, means there is a danger to life. The UK Health Security Agency (UKHSA) also raised its heat health alert to red for the same period, only the second time it has done so. Prof Robin May, UKHSA's chief scientific officer, told BBC Radio 4's Today programme that the warning signalled a "very widespread threat" from the heat, including threats "to people who generally think of themselves as not being particularly threatened by heat". He added: "Often we are warning about the vulnerable, the elderly, the young, but in this case we're also warning otherwise healthy people in their prime of life to take very cautious steps."
“Temperatures hit 34.6C as a rare red extreme heat warning prompts school closures and travel warnings across England and Wales.”
The heatwave is forecast to intensify, with temperatures in southern England expected to reach 38C on Wednesday and 39C on Thursday. That would shatter the previous June record of 35.6C, set in 1957 and equalled in 1976, though it would fall short of the all-time UK high of 40.3C recorded in July 2022. High humidity will make conditions even more uncomfortable – the Met Office warned that an air temperature of 35C could feel like 41C.
Overnight temperatures will remain above 20C in some locations, creating so-called tropical nights. The extreme heat has strained infrastructure built for a milder climate. School closures have been announced across southern England and Wales, while multiple train operators have reduced speeds and services, and the UK's largest operator urged people to travel only if essential. Hospital patient appointments have been cancelled and hosepipe bans imposed in south-east England.
The UN secretary-general, António Guterres, said in a speech at London Climate Action Week on Tuesday that London was "cooking". A rapid analysis by ClimaMeter found that climate breakdown has added 2C to 4C to the current heatwave. Across western Europe, France experienced its hottest night and then its hottest day on record, with temperatures reaching 44.3C, and officials reported 40 deaths from drowning as people sought relief. In Spain, one in eight weather stations recorded temperatures above 40C, and the national weather agency Aemet warned of "extraordinary danger".
The Met Office said the record for the UK's hottest June day was likely to be broken, but added that Tuesday's temperatures were 2C to 3C lower than forecast in south-east England after intense night-time rainfall and flash flooding in some areas. The red heat health alert remains in place until 23:00 BST on Thursday, with authorities urging people to stay hydrated, seek shade, and check on vulnerable neighbours.