Heat-related deaths

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 1980-2023.

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.

In the summer of 2023, 542 deaths were attributed to heat - around half of which occurred during the two-week heatwave in the second half of August (see report below). The highest heat-related death rates per 100,000 inhabitants were recorded in Ticino. This was followed by the cantons of the Lake Geneva region and Basel-Stadt. In rural cantons in Central Switzerland and the Central Plateau (JU, NW, UR), however, the heat-related mortality rate was similarly high. Around 95% of heat-related deaths affected people aged 75 and over and almost two thirds (63%) were women.

Development of heat-related deaths 1980 - 2023

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. 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 population's 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.

Today, it is almost exclusively people over the age of 75 who die from heat-related causes. 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 - 2026.

Until 2023, the FOPH and the FOEN only analyzed the effects of heat on deaths in Switzerland in individual, particularly hot summers such as 2003, 2015, 2018 and 2019.

However, as heat stress is expected to increase in the future, the federal government will monitor heat-related deaths on an annual basis starting in 2023.

The analyses of heat-related deaths are included in the FOEN's reporting on the state and development of the environment in the area of climate: Climate indicator «Heat-related deaths». The Federal Office for Civil Protection uses the indicator for reporting on disaster risk reduction.

Report «Monitoring of heat-related deaths: summer 2023», Ragettli et al. on behalf of the FOEN and FOPH, 2024 (in German, summary in French and Italian) (PDF, 2 MB, 24.07.2024)

Report «Monitoring of heat-related deaths 2000 to 2022 - Impact indicator ‹Heat-related deaths› synthesis report», Ragettli et al. on behalf of the FOEN and FOPH, 2023 (in German, summary in French and Italian) (PDF, 2 MB, 24.07.2024)

Climate indicator: Heat-related deaths

Der Bund erfasst hitzebedingte Todesfälle

Available in German, French and Italian.