Heat-related deaths in Switzerland are determined annually at national and cantonal level. Monitoring is carried out as part of the federal government's climate change adaptation strategy. The current time series covers the years 1980 to 2025.
High temperatures can put a strain on human health and lead to death. Due to climate change, average summer temperatures have increased in recent decades. This trend will continue in the future.
The summer of 2025 was the sixth warmest summer since records began in 1864. June and August were particularly hot, with several heatwaves lasting several days occurring across large parts of Switzerland. Between May and September 2025, 410 deaths were attributed to the heat. This corresponds to 4.5 cases per 100,000 inhabitants. During the heatwave in August, there were, in some cases, up to 25 heat-related deaths per day.
The highest heat-related mortality rate was found in the greater Ticino region, at 12 cases per 100,000 inhabitants. The lowest heat-related mortality rate was recorded in Eastern Switzerland, at around 2 cases per 100,000 inhabitants. Around 84 % of those who died as a result of the heat were over 75 years of age, even though they account for only around 10 % of the population. Around 60 % of heat-related deaths were women.
Development of heat-related deaths 1980 to 2025
As the figure below shows, the heat-related mortality rate (left axis) has not increased in parallel with the rise in the mean summer temperature (right axis) in recent decades. The proportion of heat-related deaths compared to total mortality between May and September fell by 13 % in the period 2004 to 2025 compared to 1980 to 2002, even though the average summer temperature rose from 12.9°C to 14.3°C (+1.4°C).
A certain adaptation of the population appears to be possible, especially in moderately hot temperatures. This may be a physiological adaptation or the preventive effect of heat protection measures, for example through changes in the populations behavior or structural measures.
On the other hand, the heat-related mortality rate on hot or very hot days has tended to increase over the period analyzed. This is related to the increase in such days. Here, the adaptation through the implemented protective measures seems to have had little effect.
Todey, heat-related deaths increasingly affect people over the age of 75. In the 1980s and 1990s, people under the age of 75 were also increasingly affected. Younger people appear to be more adaptable to the increasing heat and are more likely to benefit from current protective measures compared to older people.
Adaptation measures to the increasing heat
On very hot days, heat-related mortality is significantly higher than on hot or moderately hot days. Protective measures are therefore particularly important on very hot days. However, because moderately hot and hot days occur more frequently, most heat-related deaths are ultimately recorded on such days (see figure above). Overall, measures to protect the health of the population on moderately hot to very hot days are therefore important.
The Federal Office of Public Health (FOPH) is investigating which measures are being implemented and what gaps may exist in a project on the status of implementation of heat adaptation measures together with the Federal Office for the Environment (FOEN) in 2023 – 2027 (website in German).
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Last modification 09.07.2026
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