Reliable forecasts of heat-health emergencies at least one week in advance

We estimate that there were more than 181,000 heat-related deaths in Europe during the three exceptionally hot summers of 2022–2024, with 62,775 deaths during 2024 alone. Our assessment of a new generation of impact-based early warning systems shows that these emergencies can be reliably forecast at least one week ahead, enabling provision of tailored information for vulnerable populations.