Summer 2026 was Switzerland's hottest on record

Summer 2026 was the hottest recorded in Switzerland since measurements began. That is the finding of a report published by MeteoSwiss, according to which the average temperature for June, July and August reached 17.2 degrees nationwide, exceeding the previous 2003 record by 0.4 degrees.

The season brought numerous local records. On 30 July, the Basel-Binningen station reached 39.7 degrees, matching the highest value ever measured north of the Alps. In total, 30 measuring stations recorded their all-time highest temperature.

MeteoSwiss notes that a summer like that of 2026 would be considered only "moderately warm" under a scenario of 3 degrees of global warming compared to pre-industrial levels. In that case, even hotter summers would occur every two years.

The heat was accompanied by a record number of tropical days and nights, especially north of the Alps, where some locations recorded up to two additional weeks of days above 30 degrees compared to previous records. In Locarno-Monti, in Ticino, there were 50 tropical nights, eight more than in 2003. The consequences for public health were significant.

Drought and early effects

Extreme drought accompanied the heat. The period from April to August was the driest and warmest nationwide since 1901, with precipitation at only 61% of the norm. The lack of rain affected waterways, forests and agriculture.

High air temperatures, combined with reduced water flows, also pushed water temperatures to record levels in nearly 60% of measuring stations: on 14 July, the Aare in Bern reached 24.8 degrees. The heat and low oxygen levels put aquatic organisms under severe strain, with the Swiss Fishing Association reporting survival difficulties for fish.

Agriculture also suffered from the drought: the farmers' association reported a shortage of fodder and crop losses. The risk of forest fires rose to the point of prompting a nationwide ban on lighting fires, while shipping on the Rhine was also restricted.

Finally, the grass pollen season began earlier than usual and reached above-average concentrations across the country.