Western Europe experienced its hottest June on record, with two intense heatwaves increasing temperatures across the region to extreme levels, according to the EU’s Copernicus Climate Change Service (C3S).
The report underscored that heatwaves peaked between 17 and 22 June, affecting large parts of western and southern Europe. The second heatwave occured at the turn of the month, with even more extreme temperatures between June 30 and July 2 across the same region. Meanwhile temperatures soared above 40 degrees Celsius in parts of Spain and Portugal, reaching 46 degrees Celsius in some areas.
This June marks third warmest on record with the previous hottest Junes appearing in 2024 and 2023, stated C3S. The report also stated that the impact of extreme heat is being felt in Europe which is warming at twice the global average.
Much of Europe experienced above average feels-like temperature and above-average number of days with heat stress in June. Feels-like temperatures exceeding 38 degrees Celsius, corresponding to ‘very strong heat stress’, were recorded across much of southern and western Europe, particularly in Portugal, Spain, France, Italy and much of the Balkans. Northeast of Lisbon, maximum feels-like temperatures reached 48 degrees Celsius, corresponding to ‘extreme heat stress’, around 7 degrees Celsius above the average June maximum.
Samantha Burgess, the EU monitor's Strategic Lead for Climate, told AFP that the impact of the heatwaves in Europe was "exceptional", intensified by record sea surface temperatures in the western Mediterranean -- which hit an all-time daily maximum in June.
"In a warming world, heatwaves are likely to become more frequent, more intense and impact more people across Europe," she added.
The Mediterranean Sea reportedly hit its warmest temperature on record for June at 26.01 degrees Celsius on June 29. “We have never measure such a high daily temperature in June, averaged over the basin, as Sunday,” Thibault Guinaldo, a researcher at the Centre for Satellite Meteorology Studies under Meteo France told Le Monde.
Stable Grid Amid Power Surge
The 2025 heatwave triggered an increase in daily power demand as the use of air conditioners increased. According to Ember, the daily power demand by up to 6% in Germany, 9% in France and 14% in Spain, when comparing a Tuesday before (June 24) and during the heatwave (July 1).
Challenges to cooling of thermal power plants due to rising air and water temperatures also led to reductions in electricity generation from nuclear power plants in France and Switzerland. The overheating of cables likely caused power outahes in Italy on July 1.
Despite these challenges, the grids sustained the unprecedented pressures due to climate extremes by producing more solar energy during the day. In fact, June 2025 was the highest EU solar electricity production month on record – 45 TWh, a 22% increase from June 2024 (37 TWh).
