A heat dome that has parked over Western Europe since the weekend pushed temperatures at London's Kew Gardens to a provisional 35.1°C on Tuesday afternoon, the highest May reading ever recorded in the United Kingdom, and the dome was still in place on Wednesday with Italy and Spain forecast to peak above 38°C by the weekend. The Met Office said the May record for Britain had now been broken three days in a row, surpassing the previous high of 32.8°C that had stood since 1944.
At least seven people have died in heat-related incidents in France since Sunday, including a runner who collapsed at a 10-kilometre race in Paris and ten others taken to hospital in critical condition after a race in Maisons-Alfort. British police have recorded four teenagers drowned in lakes and reservoirs in England since the weekend, with a 13-year-old boy recovered from a country park in Yorkshire on Tuesday and a 15-year-old in Lincolnshire over the weekend. Italian authorities imposed outdoor working bans in five regions on Wednesday, citing labour ministry guidance issued in 2024.
Spanish forecaster AEMET said the dome would intensify over Andalusia on Friday and Saturday, with Córdoba and Sevilla likely to see daytime highs above 42°C and overnight lows that fail to drop below 25°C. Italy's civil protection agency placed eighteen cities under red alert, including Florence and Rome, where ambulance services reported a 38 per cent increase in heat-related callouts since the weekend. The Italian health ministry advised against outdoor activity between 11am and 6pm in the affected regions.
The World Weather Attribution group, a consortium of European climate scientists, said on Wednesday that breaking the British May record of 32.8°C was now around three times more likely than it would have been without human-driven warming, turning what had been a one-in-a-hundred-year event into something closer to one in thirty-three. The group described the early-season timing of the dome as "mind-bogglingly crazy" and said it was consistent with a multi-decade trend toward earlier and more intense European heat events.
European energy grids absorbed the spike better than in the 2023 heat dome, with France's nuclear fleet running near full capacity and Spain's solar output hitting a daily record of 28.4 gigawatts on Tuesday afternoon, according to grid operator REE. But peak electricity prices spiked above three hundred euros per megawatt-hour on the EPEX exchange, and Italy's grid operator Terna asked industrial users in the north to voluntarily curtail consumption on Thursday afternoon.
European Commission climate chief Wopke Hoekstra called an emergency video conference of national climate ministers for Friday, saying the dome reinforced the case for a faster implementation of the bloc's adaptation strategy. The strategy, approved last year, requires every member state to publish a national heatwave action plan by January 2027; only six have done so. France's minister for ecological transition Agnès Pannier-Runacher said her ministry would bring forward parts of its own plan, including legal heat thresholds for indoor workspaces.
Meteorologists at Météo-France said the dome would begin to weaken over the weekend, with cooler Atlantic air expected to push into Britain and northern France by Sunday. But the model consensus from ECMWF and the Met Office now points to a second, broader European heat event in the second half of June, which Britain's national climate adaptation committee chair Baroness Brown described as "the new shape of European summer."