Record heat stress affected 52% of Europe in summer 2026

Copernicus reported that a record 52% of Europe experienced very strong heat stress during summer 2026, with conditions that felt hotter than 38°C. The European Union’s climate-monitoring service also said western Europe had its hottest summer on record, while Europe overall had its third-warmest. About 80% of the continent experienced strong heat stress, defined as feels-like temperatures above 32°C. Those conditions occurred on a record 41 days by the end of the summer, according to Copernicus. Heat stress occurs when the body cannot cool itself effectively and can cause symptoms ranging from dizziness and headaches to organ failure and death. Samantha Burgess, climate lead at the European Centre for Medium-Range Weather Forecasts, which operates Copernicus, said the summer’s heat stood out for both its intensity and geographic reach. She said four of Europe’s 10 most intense heatwaves occurred during summer 2026. The August 2003 heatwave remained the most severe on record, according to her account. The effects extended beyond high temperatures. Copernicus reported that river flows across Europe fell to their lowest levels since records began in 1992.