Switzerland is experiencing its first heatwave of the year this week, with temperatures of up to 37°C and possible new June records in several regions. Heat remains the natural hazard that claims more lives in Switzerland than avalanches, floods, and storms combined, and yet it is consistently underestimated. Martina Ragettli, environmental epidemiologist at Swiss TPH, explains what this means for our health – and how Switzerland can do more.
“This week's heatwave is not a surprise. It is part of a pattern we have been observing for years: heatwaves in Switzerland are becoming more frequent and more intense.
Heat can be described as a silent killer: officially, hardly anyone dies from it directly. What heat often does is aggravate existing conditions such as cardiovascular disease, diabetes, and respiratory illness. This link rarely shows up in official mortality statistics.
Since 2023, we have been running an annual heat-related mortality monitoring programme on behalf of the Swiss Federal Office of Public Health. The data shows that a hot day of 32°C causes fewer deaths today than it did twenty years ago. In recent summers, around 500 deaths per year have been attributed to heat. Compared to around 1,400 during the 2003 heatwave, this marks a significant decline that points to the impact of adaptation measures in recent years.
But adaptation is not happening fast enough. Switzerland has made progress on short-term measures such as public awareness campaigns, cooling spots, and neighbourhood support for older people. Many Swiss Cantons have also introduced heat action plans. A recent study across 102 European cities, to which we contributed, confirms their effectiveness: heat action plans can reduce heat-related mortality by around 25%.
At the same time, gaps remain. Heat action plans should be implemented across the board and should include not only short-term but also long-term protective measures. There is also need for action regarding the preparedness of healthcare facilities. Our 2025 survey of nursing and care staff found that four out of ten facilities had no measures in place to protect patients and clients from the heat. Schoolchildren and people who work outdoors also need better protection.
Long-term measures also require more attention through urban planning and architectural changes. More green spaces and climate-adapted buildings not only provide protection against heat, but also support recovery, physical activity, social connection, and mental well-being.
Through the CCHeSS study, we are currently investigating how high temperatures affect the health, well-being, behaviour, and use of health services among the Swiss population. Around 1,200 participants are completing regular questionnaires throughout the summer – and this week's heatwave is giving us real-time data to work with. The findings will help develop more targeted protective measures, because heat will challenge us more often and more severely in the years to come.”
For press enquiries, please contact communications@swisstph.ch.
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