Record-low lakes and crop losses expose Switzerland’s drought costs

Eastern Switzerland’s lakes have reached record lows as the country counts the cost of a summer of heat, drought and hail. On Wednesday, the Untersee, the western section of Lake Constance, stood 4 centimetres below its lowest recorded level, set on January 14, 1949. Measurements at the site began in 1885.

The consequences are visible along the shoreline. Boats have remained aground through much of the summer, and the harbour at Mannenbach-Salenstein has faced a clear shortage of water since June. In parts of canton Thurgau, smaller water bodies have reached historically low levels or dried out completely.

The same weather pattern has damaged fields and weakened the wider economy. Hagel Schweiz estimates CHF 59.2 million in crop losses, while Allianz Trade puts the heatwave’s overall economic cost at CHF 400 million. Together, the figures show how a dry season moves through Switzerland’s economy, from farms and insurers to transport, labour and local businesses.

The drought has also persisted longer than a single hot spell. Forecasts cited by Swissinfo indicate that September could become the sixth consecutive month with below average rainfall, leaving communities and farmers with little time to rebuild water reserves.

Lake Untersee has broken a low water record that stood for more than seven decades. The measurement is significant because the lake has one of Switzerland’s longest hydrological records, extending back to 1885. Its latest fall below the 1949 level reflects months of limited rainfall, weak inflows and intense evaporation.

Lake Walen offers another measure of the pressure. Its level reached 418.18 metres above sea level, the lowest September reading recorded at that station. It remains above the lake’s all time low, which was measured on February 14, 1949, when the water stood 26 centimetres lower.

Low levels in Lake Walen are also affecting the Linth, the main tributary flowing into Lake Zurich. Very little water is now moving from the lake into the river. Lake Constance faces a similar supply problem. Although around 200 tributaries feed the international lake, the Rhine provides approximately 62% of its water. The stretch between Chur and the Rhine’s entry into Lake Constance is among the areas classified as experiencing extreme drought by the Federal Office for the Environment.

Canton St Gallen’s assessment says this year’s drought is worse than those of 2003 and 2018, after a second winter with little snow and repeated summer heatwaves.

Swiss agriculture is facing CHF 59.2 million in insured crop damage after the driest and hottest April to August period since records began in 1901. Hagel Schweiz expects approximately 5,800 claims for the year, almost three times the damage recorded last summer.

Drought accounted for 45% of claims, while hail accounted for 48%. The two hazards often compound one another. Plants weakened by a lack of water have less capacity to recover when severe storms arrive, while hail can destroy crops that farmers have already carried through a costly dry season.

Summer crops suffered particularly heavy losses. Potatoes, maize, sugar beet and sunflowers were among the hardest hit, leaving farmers facing reduced yields and insurers facing unusually high compensation payments. Hagel Schweiz expects the claims burden to produce a significantly negative operating result.

The damage reaches beyond individual fields. Lower harvests can affect food processors, animal feed supplies and farm cash flow. Farmers may also face higher costs for irrigation, replanting and soil management in future seasons. The insurer’s assessment places this year’s events within a longer climate trend. “This year’s drought clearly shows just how much agriculture is already suffering from the effects of climate change,” Hagel Schweiz said.

The heatwave’s estimated CHF 400 million economic cost extends well beyond farms and lakeshores. Allianz Trade calculates that the losses equal around 0.05% of Swiss gross domestic product. Extreme heat reduced labour productivity, as workers needed longer breaks and illness led to additional absences.

The estimate captures a broad economic effect. Businesses must manage disrupted work, higher cooling needs and weather related uncertainty, while farmers and insurers absorb direct losses. Local economies around affected lakes also face pressure when low water restricts boating, harbour activity and lakeside commerce.

Jan Möllmann, CEO of Allianz Trade in Switzerland, said that “climate change is increasingly becoming an economic factor”. The insurer plans to publish an annual assessment through the Allianz Climate Risk Tracker, giving companies and policymakers a regular view of the costs of extreme weather.

The study also points to risks beyond this summer. Allianz Trade and Allianz estimate that a strong El Niño could cost the global economy around $451 billion in 2027, with Europe facing an expected net loss of approximately €21 billion. Switzerland’s share would depend on the severity of future heat, rainfall and storm events, as well as the country’s capacity to prepare.

Around one fifth of Swiss monitoring stations recorded their lowest water levels for the period between April 1 and July 31. The data shows that the drought is national in reach, even though the sharpest visible impacts have emerged in eastern Switzerland. A second winter with little snow reduced the water stored in the Alps before summer heat increased demand and evaporation.

The immediate outlook remains difficult. No significant rainfall was expected through the end of September in the forecast cited by Swissinfo. That leaves less water entering rivers and lakes, while farmers, households, businesses and ecosystems continue to draw on supplies.

Allianz Trade’s analysis argues that early warning systems, risk maps and clearly assigned responsibilities improve resilience. Those tools matter when authorities must coordinate water use across cantons, agriculture, energy, transport and environmental protection. Lake Constance also requires cooperation across national borders because the lake is shared by Switzerland, Germany and Austria.

Switzerland has seen both extremes in a short period. In June 2024, heavy rain pushed Lake Constance to its highest flood alert level, submerging promenades, car parks and garden restaurants. In 2026, exposed shorelines and grounded boats show the opposite pressure. Hydrological planning now has to account for both rapid flooding and prolonged water scarcity.