Red extreme heat warning issued as temperatures could reach 40C

A rare red extreme heat warning has been issued by the Met Office as temperatures are forecast to rise as high as 40C (104F) later this week.

The warning, covering parts of the Midands, south-east Wales and southern England, will be valid from 09:00 GMT on Wednesday to 21:00 on Thursday as exceptionally hot and humid conditions threaten a large swathe of the UK.

The Met Office is also warning of substantial disruption to travel, energy supplies and possibly widespread damage to property and infrastructure.

Red warnings are rare, only issued in the most extreme cases indicating that the weather could bring a risk to life.

Historically we only have around one red warning issued a year, the last being during Storm Goretti in January 2026 when dangerous winds hit Cornwall and the Isle of Scilly.

A red extreme heat warning is even rarer, this being only the second time a red warning has been issued since extreme heat warnings began in 2021.

The previous being issued in July 2022 when we saw the UK's highest temperature on record of 40.3C in Coninsby.

Forecasters are warning humidity is likely to be significantly higher during this heatwave compared to 2022 and that heat stress is a major concern, even in the general population.

Daytime temperatures are expected to exceed 30C widely across the warning area, with the hottest locations potentially reaching around 39C.

If we reach 40C, this will come close to the UK's all-time record of 40.3C set in July 2022.

Overnight temperatures will also be significant and likely record breaking across England and Wales.

Some urban areas will struggle to fall below 21 or 22C, resulting in a so-called tropical night.

In addition to the Met Office warnings, the UK Health Security Agency has also ugraded existing heat-health alerts to red across the Midlands, eastern and southern England.

They will be valid from 01:00 GMT on Wednesday 24 June to 23:00 GMT on Thursday 26 June.

Red heat-health alerts are considered an emergency response and indicate that "severe impacts expected across health and social care services" with an increased risk to life across the whole population.

Amber heat-health alerts have also been issued across Northern England for the same times.

The heat is spreading from continental Europe where an extremely intense hot spell has developed.

Temperatures in parts of western France could climb to 43 or 44C over the next few days.

Red heatwave alerts have been issued for about half of the country on Monday. Paris is likely to reach 40C (104F), which would be unprecedented for June.

In the UK, very hot conditions are expected to continue until at least Thursday.

The Met Office says cooler conditions may begin to edge in from the west late in the week, although confidence in the timing and extent of any breakdown remains low.

As with previous heatwaves, scientists say rising global temperatures caused by human-induced climate change are making extreme heat events more frequent and more intense in the UK.