WESTERN EUROPE is in the grip of a blistering heatwave. Several countries have broken June temperature records. Roads in France are beginning to melt. Britain has closed schools and cancelled hospital appointments. The whole continent is warming faster than any other and, compared with other rich regions, is poorly equipped to handle the heat. Our analysis is an early look at which cities might suffer most this time round.
Two women sitting in a touristic boat on the river Spree shelter from sun with large sunheats in the center of Berlin on June 26, 2026. (AFP)
Death tolls will be determined not just by absolute temperatures, but by how unusual they are. In 2023 Pierre Masselot and colleagues at the London School of Hygiene & Tropical Medicine modelled the relationship between temperature and mortality in 854 cities across Europe. They found that when cities experience freakishly high temperatures people fare worse: 30°C (86°F) in Manchester is far more deadly than in Madrid. Neither bodies nor buildings are adapted to cope. Dark materials such as concrete and tarmac retain heat more than greenery, and pollution exacerbates the ill effects of heat.
To estimate how deadly the current weather might be, we combined Dr Masselot’s model with the average forecasted temperatures for June 24th to 26th—the peak of the heatwave. This is imperfect: it does not consider factors such as humidity. But it does partly account for nighttime heat, which is one reason why this heatwave has been so dangerous (it means the body has little time to recover). And the method produces a back-of-the-envelope estimate of the increased risk of death in 854 cities relative to days with the most comfortable temperatures, when mortality is lowest.
The results show that, in just three days, the extreme heat could cause around 12,000 excess deaths. Paris’s mortality rate could rise by more than 300%—the biggest increase in our analysis. Temperatures in the city have been particularly anomalous, well above the 99.9th percentile of those between 2000 and 2019. Parisians often suffer higher death tolls during heatwaves, perhaps because of the heating effect of the city’s iconic grey zinc roofs. London’s risk of death could surge by roughly 200%; Milan’s by 170%.
Thousands of Europeans die every summer. Clair Barnes of Imperial College London and colleagues estimate that 24,400 people were killed by extreme heat between June and August 2025. Older residents tend to be most vulnerable: 85% of last year’s victims were over the age of 65. Studies have also found that women are more affected than men and that big cities tend to fare worse than smaller ones. Our estimates are only a rough guide based on historical averages. Quantifying the true effect of this heatwave will take time. By then, Europe may have been hit by another.
