A rare red extreme heat warning has been issued for parts of England and Wales, with temperatures forecast to reach 40°C – a level that has only been recorded once before in the UK. The warning, issued jointly by the Met Office and the UK Health Security Agency (UKHSA), indicates a risk to life even for healthy people, and triggers emergency responses across health services, schools, and transport networks.
A red extreme heat warning is the highest level of alert in the UK's weather warning system. It is issued only when dangerously hot weather is expected and significant impacts are likely. The Met Office's red warning for extreme heat covers southern Wales, London, and a swathe of England from Kent to Somerset and up to Birmingham. The UKHSA's red heat health alert covers the East Midlands, West Midlands, East of England, London, South East, and South West. Both warnings run from early Wednesday to late Thursday. An amber warning, which is serious but less severe, covers most of the rest of England and Wales.
“Explains the UK's red extreme heat warning system, its risks, and how to stay safe.”
These warnings are extremely rare. The only previous red extreme heat warning from the Met Office was issued in July 2022, when temperatures reached 40.3°C in Coningsby, Lincolnshire – the highest ever recorded in the UK. That heatwave also prompted the first ever red heat health alert from the UKHSA. Before that, the hottest June day was 35.6°C in 1976. Scientists have noted that recurring heatwaves are a marker of global warming: of the 51 heatwaves recorded in France since 1947, 34 have occurred since 2000 and 26 since 2011. In the UK, forecasters predict that in 30 years' time, 45°C heatwaves could become possible, fundamentally changing British life.
For UK readers, the practical impact is immediate and serious. High humidity accompanying the heat makes conditions feel even more uncomfortable and reduces the body's ability to cool down at night. The UKHSA warns of severe impacts across health and social care services, with an increased risk to life across the whole population. Schools in affected areas are closing early or sending pupils home. The AA has warned drivers that heat can put extra strain on vehicles, and gritters may be deployed on roads to prevent tarmac from melting. The public is advised to stay out of the sun between 11am and 3pm, keep hydrated, and check on vulnerable neighbours.
Q: What does a red extreme heat warning actually mean? A red warning means dangerous weather is expected and you should take action to protect yourself and others. The Met Office says it indicates a genuine risk to life, substantial disruption to travel and energy supplies, and possible widespread impacts on property and infrastructure. It is the most severe weather alert and is only issued in exceptional circumstances.
Q: How rare is a red heat warning in the UK? Extremely rare. The Met Office has only issued a red extreme heat warning twice: in July 2022 and now in June 2026. The UKHSA red heat health alert was also first used in 2022. Before 2022, the UK had never experienced temperatures above 40°C.
Q: What should I do during a red heat warning? Stay indoors during the hottest part of the day (11am to 3pm), keep your home cool by closing curtains, drink plenty of water, and avoid strenuous activity. Check on elderly or vulnerable relatives and neighbours. Never leave children or pets in parked cars. If you feel unwell, seek medical advice.
The heatwave is expected to peak on Wednesday and Thursday, with temperatures potentially reaching 40°C. By Saturday, the Met Office forecasts temperatures could drop by as much as 15°C as Atlantic low-pressure systems move in, bringing cooler, more changeable weather. However, the far southeast may retain some heat initially. Looking further ahead, scientists warn that such heatwaves will become more frequent and intense as the climate continues to warm.