A powerful heat dome of warm air from northern Africa, trapped under a high-pressure system over western Europe, has brought record-breaking May temperatures to the UK, France, Spain and much of the continent, with forecasters warning of a prolonged period of extreme heat not usually seen until high summer. The atmospheric pattern, often referred to as a “heat dome”, is characterised by sinking air, clear skies and limited atmospheric mixing that holds hot air in place and pushes temperatures well above seasonal norms.
In the United Kingdom, the Met Office recorded the hottest May day on record on Monday, May 26, 2026, with temperatures hitting 34.8°C at Kew Gardens in southwest London, a full two degrees above the previous May high. The Met Office noted that this heat would be exceptional even in mid-summer, let alone May, when temperatures normally average about 17°C or 18°C. London saw 35.1°C in some areas, with British authorities reporting that temperatures in parts of the country were 17 degrees above seasonal averages.
France also logged its hottest May day in history, with an average temperature of 24.9°C on May 26 and daytime highs peaking at almost 40°C in several regions two days later. Météo-France attributed the spike to the heat dome pushing temperatures more than 10°C above seasonal norms, and placed Paris under yellow alert with forecasts of 35°C. At least seven deaths in France, five from drowning, have been tied to the sweltering conditions. The heat affected major events including the French Open, where top-ranked player Jannik Sinner was eliminated after taking a medical time-out for cramping likely caused by dehydration.
Spain was expected to peak later in the week at 38°C, with the city of Badajoz reaching 38°C, the first time in 71 years of records for this time of year. Portugal broke its May temperature record as well, with the town of Mora hitting 40.3°C, besting the previous peak of 40°C set in 2001. Parts of Italy imposed restrictions on working outdoors and Rome, Florence, Bologna and Turin were placed on the highest health alert, with temperatures reaching 32°C in Florence and Bologna and 31°C in Rome.
The early-season heat has been made three to five times more likely because of climate change, according to Climate Central’s Climate Shift Index. Scientists say human-induced climate change is making heatwaves, droughts and floods more intense, with Europe warming faster than the global average. Met Office meteorologist Greg Dewhurst called the increase in extreme temperatures “a good indication of climate change in action” and more likely to become “the new norm”. Climate advisers warned the UK government last week that the country was “built for a climate that no longer exists” and urged adaptation of infrastructure like schools and hospitals for a warming planet.
Early-season heat events place additional pressure on infrastructure and public health because populations and urban systems are generally less acclimatised to prolonged heat after the colder season. Unlike the US, where an estimated 90 percent of households have air-conditioning, only about 20 percent of European homes are equipped, making high temperatures particularly dangerous. Restrictions on outdoor work were imposed in parts of Italy, beaches in southwest France filled earlier than usual, and farmers reported accelerated harvests. The heat dome extended across Western and Central Europe, with Germany, Switzerland, the Netherlands and Belgium also recording temperatures well above late-May norms, and Switzerland experiencing its fourth hottest May since records began in 1864.
