Switzerland’s record summer brings heat drought and future risks

Switzerland experienced its hottest summer since records began in 1864, with heat and drought causing low water levels, fish deaths, crop losses and severe glacier melt, SRF reported on Thursday.

According to MeteoSwiss’s climate bulletin, the average temperature from June to August was 17.2 degrees, nearly 0.4 degrees higher than in 2003. The summer of 2026 is therefore the country’s new record.

Many places recorded more days with temperatures of at least 30 degrees than ever before. The 35 degree mark was also exceeded more frequently than in any previous year. Several locations recorded all time highs for daily temperatures.

Binningen in Basel-Landschaft recorded the highest temperature ever measured on the northern side of the Alps, at 39.7 degrees. Heatwaves also lasted unusually long, in some cases for more than 20 days. At the same time, rainfall fell to minimum levels in some places.

Water shortages affected nature and farming

Lake and river levels fell, while many streams carried no water at all and some springs dried up. Where water remained, it was often very warm. The Aare reached a record temperature of 24.8 degrees.

The combination of heat and drought created serious problems for fish. Experts expect massive fish deaths this year. Forests turned brown, with leaves changing colour as early as July in some places, although the full extent of the damage is not yet known.

Yellow meadows were another visible sign of the drought. Agriculture also faced shortages of animal feed and crop losses. Glacier melt was severe, while groundwater levels fell to very low levels in some places.

Warm seas add to the risks

The heat affected the seas as well as the land. According to a Copernicus report, the seas were warmer last August than ever before.

Warmer water expands, causing sea levels to rise. It also contributes to the melting of sea ice and glaciers that extend into the sea, further raising sea levels. Marine heatwaves put pressure on animals and plants, including corals. Ocean currents could also change, although researchers are still working to understand the effects.

A possible preview of future summers

SRF science editor Felicitas Erzinger said the summer was a clear preview of what is to come and matched climate model projections. In a world that is three degrees warmer, which current trends are roughly approaching, a summer like this would be average. About one in two summers could be even hotter, and some could also be drier.

Future water management will require storing as much water as possible in cities, on farms and in forests, using measures such as ditches, basins and ponds. Switzerland also needs better data on water consumption, including by agriculture, industry, power stations and drinking water suppliers, so decisions can be made about allocation during shortages.

The effects of this summer could continue for months, particularly in groundwater levels. Winter is essential for replenishing groundwater reserves. If autumn and winter bring less rain than usual, the effects could be felt next year.

The winter of 2025 to 2026 was already short of snow, followed by little rain in spring. Both factors contributed to this summer’s drought.