Historic May heatwave grips Europe: France reports seven deaths, UK shatters records as temperatures soar past 37°C

A powerful and persistent heat dome is baking Western Europe, delivering temperatures more typical of mid-summer than late spring. The phenomenon, driven by a stable high-pressure system named Alexander that is trapping hot air from North Africa, has triggered widespread temperature records and public health warnings across multiple countries.

France: A historic and deadly event

France is at the epicenter of the crisis. The national weather service, Météo-France, confirmed that Monday was the hottest May day ever recorded nationally. New monthly maximums were set at over 350 weather stations, predominantly in the west of the country, with the mercury hitting 37.1°C in Hossegor in the southwestern Landes department. Temperatures have been up to 13°C above seasonal norms.

We are talking about an exceptional, historically unprecedented episode. All superlatives are allowed to describe this current weather phase.

The human toll is mounting. Government spokesperson Maud Bregeon announced that seven people have died in circumstances "directly or indirectly linked to the current heatwave." At least five of the victims drowned, while two others died during sporting activities in Paris and the greater Lyon area. Authorities have urged the public to exercise extreme caution. For the first time ever in May, eight departments in western France were placed under an orange heat alert.

United Kingdom: Records tumble day and night

The UK is also experiencing a historic heat event. The Met Office reported that Heathrow recorded 33.5°C on Bank Holiday Monday, smashing the previous May record of 32.8°C set in 1922 and matched in 1944. The heat persisted overnight, with the London suburb of Kenley not dropping below 21.3°C, marking the warmest May night since records began. Forecasts suggest temperatures could reach 35°C in parts of southeast England and Wales on Tuesday.

Records are usually broken by only tenths of a degree — which makes this heatwave unprecedented for this time of year.

The heat dome phenomenon

The extreme weather is caused by a "heat dome," a blocking weather pattern where a high-pressure system stalls over a region for an extended period. This traps hot air from North Africa over Western and Central Europe, preventing cooler air masses or rain fronts from moving in. The sun heats the ground unimpeded, creating a self-reinforcing cycle of escalating temperatures.

Wider European impact

The heatwave's reach extends far beyond France and the UK. In Spain, temperatures in Seville hit 39°C over the weekend, with forecasts predicting the 40°C mark could be breached this week. Switzerland saw the 30°C threshold crossed on May 22, and meteorologists expect widespread May records to fall in the south of the country on Wednesday, with highs of 32-33°C. Germany is experiencing the peak of the heatwave, with the German Weather Service forecasting 29-34°C in the southwest, though the country remains on the edge of the heat dome. The heat is expected to persist until at least the end of the week.

Climate change context

Scientists have been unequivocal in linking the event to climate change. Météo-France stated that such heat levels at this time of year are a clear consequence of global warming, noting they would have been impossible 30 or 40 years ago. Climate scientist Christophe Cassou described the event as having a one-in-1,000 probability of occurring at this time of year based on 1979-2025 climate data, and "practically impossible in the pre-industrial era."