Water levels on Lake Constance have dropped to a 53-year low, data from Canton Thurgau has revealed. Persistent drought across Switzerland and southern Germany has led local rivers and lakes to dry up.
According to officials from Canton Thurgau, quoted in the Thurgauer Zeitung, the water level in the western Untersee section of Lake Constance is at its lowest level recorded for April since 1972, and is likely to fall further. In the larger Obersee section of the lake, the water line is 40 centimetres below the average for the time of year, the lowest level reported since April 1996.
Lake Constance is one of just two large Swiss lakes whose water level is not regulated by dams - the other being the Walensee. As a result, the low water line is already having a big impact: Mannenbach harbour has completely dried up, while Hoy Island in Bavaria, which can usually only be accessed by boat, is now connected to the mainland by a small path.
The main reason for the low water level is persistent drought which has afflicted the region and the mountains that feed the lake. In Switzerland, March 2025 was persistently too dry, with some areas of the Alps seeing 80 percent less rain and snowfall than usual. "Snow depths in the catchment area are below average, which indicates that snowmelt will be lower this year than in other years," said a Thurgau spokesperson.
Thanks to climate change, periods of warm, dry weather are becoming more frequent and severe in central and southern Europe, culminating in droughts and heatwaves. Experts argue that unless freak weather intervenes, the water line at the lake will continue to drop as Switzerland enters summer.