Switzerland experienced its third-warmest June since temperature records began in 1864, as a historic late-month heat wave pushed temperatures to record highs across the country, the Federal Office of Meteorology and Climatology (MeteoSwiss) said on Tuesday.
The national average temperature in June was 3.5 degrees Celsius above the 1991-2020 average, making it the third-warmest June on record after 2003 and 2025, Swissinfo reported.
Meteorologists described the late-June heat wave as being “of historic proportions” because of its exceptional combination of duration and intensity.
Several weather stations, including Basel, Neuchatel, and Zurich, recorded their hottest 10-day periods since observations began.
Basel-Binningen reached 39 degrees Celsius (102.2 degrees Fahrenheit), setting a new all-time temperature record for German-speaking Switzerland. Daily maximum temperature records were also set in Neuchatel at 38.1C (100.6F) and Zurich-Fluntern at 37.1C (98.8F). Bern-Zollikofen also recorded 13 consecutive days of high temperatures, a local record.
MeteoSwiss said a heat wave of similar or greater intensity at this time of year remains rare, occurring less than once every 25 years despite climate change.
The agency said the event resulted from a combination of a persistent high-pressure system over Europe and a warmer climate, adding that climate change made the heat wave significantly more likely and more intense.
According to an analysis by World Weather Attribution cited by MeteoSwiss, a comparable heat wave would have been virtually impossible 50 years ago, when temperatures were about 3.5C lower.
The agency warned that Swiss climate projections indicate such heat waves are expected to become more frequent and potentially more severe as global warming continues.
June was also drier and sunnier than normal, with some regions receiving less than 40% of their average rainfall.
The prolonged dry conditions prompted authorities to raise drought warnings to the highest level across large parts of the country after rainfall between April 1 and June 28 fell more than 170 millimeters below average nationwide.
