Switzerland Braces for Fourth Summer Heatwave as Drought Shows No Sign of Easing
Meteo Swiss forecasts 37°C in Geneva this week while the Federal Office for the Environment warns that the ongoing drought is unlikely to ease, with lake levels still falling.
Switzerland is bracing for its fourth heatwave of the summer, with weather models agreeing that from mid-week temperatures will exceed 30°C across much of the lowlands. Meteo Swiss predicts 37 degrees in Geneva by Thursday and 35 degrees in Zurich, marking another stretch of extreme heat in a summer that has already seen three previous heatwaves.
The Federal Office for the Environment (FOEN) warned that the widespread drought is unlikely to ease significantly despite expected thunderstorms. Maximum temperatures of up to 37 degrees are expected from Wednesday onwards in western and German-speaking Switzerland, piling additional stress onto landscapes that have been parched for weeks.
Water levels in Switzerland’s lakes and rivers are still falling. Lake Maggiore has dropped by more than one meter since mid-June, and the most acute conditions run from the Jura Mountains through Basel, where precipitation over the past 30 days has been up to 70% below normal. That deficit, combined with the coming heat, will accelerate evaporation and further strain water supplies.
The sequence now is grimly familiar: a fourth heatwave arriving while a drought that began weeks ago still has no end in sight. FOEN has said that even the thunderstorms that usually bring temporary relief are unlikely to break the pattern in any meaningful way. The ground is too dry, the catchments too depleted, for scattered downpours to reverse months of below-average rain.
With no significant rainfall forecast beyond the weekend and temperatures set to remain above 30°C well into next week, Switzerland is entering a period where the compounding effects of heat and water scarcity will be felt from Alpine pastures down to the largest lakes. The summer of 2026 is turning into a stress test for the country’s water infrastructure, and for now, the numbers are only trending in one direction.