Forecasters warn the heat could exceed 35.6C, the current highest June temperature recorded in Southampton in 1976.

The Met Office has extended its amber extreme heat warning from Monday to Thursday, covering most of southern England, central and eastern Wales, and much of the Midlands, with the alert spreading north to parts of Greater Manchester, Yorkshire, and Cheshire midweek.

You can see the full weather forecast via the Met Office.

Weather warnings expanded as UK to reach 38°C heat

Met Office meteorologist Jonathan Vautrey said: "I’m sure many of us will be wanting to get outside and enjoying some of this heat, but it certainly is worth taking care as we could see some impacts around."

"It’s particularly across central southern regions, where we have an extreme heat warning, an amber extreme heat warning issued, where we could see quite widely amongst the population some heat-related impacts throughout the week."

The warning highlights risks not only for vulnerable people but also for the wider public, with advice to stay hydrated, avoid the sun, and refrain from exercising between 11am and 3pm.

The UK Health Security Agency (UKHSA) has issued separate amber heat health alerts covering most of England from Monday morning until Friday night, with a yellow alert in place for north-east England.

Mr Vautrey also raised concerns about water safety.

⚠️⚠️ Amber weather warning issued ⚠️⚠️

Extreme heat across parts of central and southern England and Wales

Wednesday 24 and Thursday 25 June

Latest info 👉 https://t.co/QwDLMfRBfs

Stay #WeatherAware ⚠️ pic.twitter.com/ZReUbaplO9

— Met Office (@metoffice) June 21, 2026

He said: "Water safety as well is going to be paramount if you are by the coast or other water bodies in land as well, and do follow the safety advice of relative authorities in order to avoid the cold water shock when you are heading into any water areas."

The warning follows a hot spell in May during which at least 15 people died in open water incidents.

Samantha Hughes, national water safety partner at the Royal National Lifeboat Institution, said: "With warmer weather approaching, it’s important to remember that the water is still cold.

"Entering it unexpectedly can lead to cold water shock, causing a sudden increase in breathing and heart rate, which may trigger panic."

Monday is expected to be cloudier, with temperatures up to 32C and rising humidity later in the week.

Highs of 31C are forecast in London, 27C in Cardiff, and 21C in Scotland and Northern Ireland.

NHS England reported that visits to its hay fever advice webpage more than doubled last week following hotter weather.

Duncan Burton, chief nursing officer for England, said: "People should be careful not to double-dose on medication which might make them drowsy, particularly if planning to drive."

The highest temperature recorded in the UK so far this year is 27.7C, measured on Saturday in Writtle near Chelmsford, Essex.

Health and safety officials in the UK have reminded employers of their responsibilities during the hot weather.

The Health and Safety Executive (HSE) said employers must ensure workers are protected while maintaining productivity during the extreme heat period.

Are you enjoying the heatwave? Let us know in the comments.