In France, authorities placed several western départements under a yellow heatwave alert from Monday lunchtime as temperatures climbed far above seasonal averages. In Nantes, thermometers reached around 34 to 35C, breaking local May records including a high of 34.3C.
Across the Channel, the United Kingdom recorded its hottest May day since national records began. Temperatures reached 34.8C at Kew Gardens in London, surpassing the previous May record of 32.8C set in 1922 and matched in 1944.
Parks, fountains and shaded public spaces filled with residents and tourists seeking relief from the heat, while health officials urged people to stay hydrated and avoid outdoor activity during the hottest hours of the day.
Further south, meteorologists warned that temperatures in parts of Spain could rise into the mid-30s later this week, with some inland regions expected to approach or slightly exceed 38C. Forecasters described such conditions as highly unusual for late May and a sign of increasingly frequent early-season heat extremes.
Scientists say climate change is making heatwaves across Europe earlier, longer and more intense. During this late-May episode, temperatures rose by as much as 10 or 11C above seasonal averages in parts of France, the United Kingdom and Spain. The heat has already been linked to several heat-related illnesses and to the death of a man who suffered a cardiac arrest during a race in Paris over the weekend.