More than 35,000 excess deaths during a succession of heatwaves that pushed western Europe into exceptional climatic territory
Behind every temperature record lies a human impact. The summer of 2026 brought successive episodes of extreme heat across much of western Europe and left an unmistakable signal in mortality surveillance systems. By the end of August, a compilation of national data estimated at least 35,000 excess deaths during Europe’s successive heatwaves. Even then, the figure was incomplete: it covered only just over half of the continent and did not yet include all the data from August.
2026 in four figures
Note: national figures cannot be added together directly because they use different methods and cover different periods.
A silent crisis that is not measured in the same way everywhere
Extreme heat is one of Europe’s deadliest natural hazards, yet its impact is less visible than that of a flood or wildfire. Most people do not die from a heatstroke formally diagnosed as such. Excessive heat aggravates cardiovascular, respiratory, renal and metabolic diseases, increases dehydration and forces the body to work harder to maintain a stable temperature.
This is why health surveillance systems use statistical models. They compare the number of people who die during a given period with the number of deaths that would normally be expected, or estimate the proportion of mortality that can be attributed to temperature. This methodological distinction is crucial: “excess mortality”, “heat-attributable mortality” and “heat-related mortality” do not mean exactly the same thing.
Germany: an estimate more than twice the worst recent years
The Robert Koch Institute estimates around 16,000 heat-related deaths in Germany up to week 36 of 2026, with an uncertainty interval of 14,300 to 17,600. The estimate remains provisional, but its magnitude is extraordinary. In 2018 and 2019, previously among the most severe years in the recent series, the institute estimated around 7,000 heat-related deaths.
The most critical episode occurred in late June, when Germany and other parts of western Europe experienced exceptionally high temperatures. The jump compared with recent summers shows that the problem is not simply a matter of a single daily maximum: the duration of the heat, warm nights and cumulative exposure in an ageing population also matter.
France: 53 days under heatwave conditions
France experienced three heatwaves lasting a combined 53 days over the summer, an unprecedented total according to Météo-France. The first major heatwave, from 17 to 30 June, was also the most intense observed since 1947 and pushed the national mean temperature to 30 °C on 24 and 25 June.
The health impact was immediate. Santé publique France estimated 5,764 deaths above the expected level during the episode from 17 June to 2 July. It subsequently estimated 1,243 excess deaths during the July episode and a further 817 between 27 July and 20 August. These are estimates of all-cause excess mortality during the days and départements affected by heatwave conditions; they are not equivalent to individual death certificates recording “heat” as the cause of death.
Spain: the hottest summer since at least 1869
AEMET’s climate assessment places the summer of 2026 in a historic position. The mean temperature across mainland Spain was 24.5 °C, 2.4 °C above the 1991–2020 average. It was the hottest summer in the official series, which begins in 1961, and the available climate reconstruction indicates that there has been no hotter summer since at least 1869.
AEMET identified four heatwaves during the summer: three across mainland Spain and the Balearic Islands, and one in the Canary Islands. A fifth heatwave then occurred in early September. The summer quarter was also very dry: average rainfall across mainland Spain was only 56% of normal, making it the third-driest summer since 1961.
In terms of health, the MoMo system run by Spain’s Instituto de Salud Carlos III estimated 5,091 deaths attributable to high temperatures during June, July and August. This is the highest figure since the start of the series used by the system. These deaths are not necessarily concentrated on days officially classified as heatwaves: risk can also increase during prolonged periods of high temperatures that do not exceed every meteorological threshold.
The problem also reaches northern Europe
The impact of 2026 was not confined to the Mediterranean. The UK Health Security Agency estimated 2,877 heat-associated deaths in England during two episodes in May and June: 753 in May and 2,124 during the June heatwave. These are interim figures and refer only to those two periods.
Geography matters. Many regions of central and north-western Europe have buildings, urban infrastructure and social habits that historically evolved for less extreme climates. When nights no longer cool down, homes retain heat for several days and the body has less opportunity to recover.
Western Europe at the centre of the 2026 heat
Copernicus ranks the summer of 2026 as Europe’s third warmest across the continent as a whole since 1979, with an anomaly of +1.17 °C relative to 1991–2020. But the continental mean conceals a crucial contrast: western Europe recorded its hottest summer in the ERA5 series.
The region’s mean summer temperature reached 21.69 °C, 2.54 °C above the 1991–2020 average. France, England and north-eastern Spain were among the areas with the largest seasonal anomalies. This helps to explain why some of the most severe health impacts were concentrated in this part of the continent.
The fingerprint of climate change
World Weather Attribution analysed the June heatwave in France, Germany, Italy, Spain and southern England. Across large areas, temperatures were between 5 and 12 °C above the values normally expected at that time of year.
The study concludes that a similar atmospheric set-up would have produced daytime temperatures around 3.5 °C lower in the climate of 1976. In other words, the weather patterns that generate heat are not new, but they now develop in a significantly warmer atmosphere. The same type of circulation therefore produces much more severe extremes.
Warm nights deserve particular attention. The human body needs to shed the heat accumulated during the day. When night-time temperatures remain high, that recovery is reduced and stress on the cardiovascular and respiratory systems increases, particularly among older people and those with chronic illnesses.
From heat to soil: drought, vegetation and wildfires
For NEST, the summer of 2026 offers another important lesson: the crisis does not end with air temperature. Persistent heat increases atmospheric evaporative demand and accelerates water loss from soils. When rainfall is scarce, less moisture is available to vegetation, crop stress intensifies and landscapes become more flammable.
World Weather Attribution concluded that human-induced warming substantially increased the likelihood and severity of the conditions that favoured major wildfires in France and Spain during 2026, including severe soil-moisture deficits. This does not mean that climate change “ignites” every fire, but it does alter the conditions under which an ignition can spread and develop into an extreme event.
EFFIS data show that, by 23 September, around 679,000 hectares had burned in the European Union in fires larger than 30 hectares. This was below the exceptional total recorded in 2025, but almost twice the average for the previous two decades at the same point in the year. After a fire, the loss of vegetation cover can increase erosion, alter soil organic matter and microbial communities, and temporarily reduce the soil’s capacity to regulate water and carbon.
The real record may be persistence
Major headlines tend to focus on a single day’s maximum temperature. From a health and ecological perspective, however, persistence may be even more important. Consecutive weeks of heat accumulate stress in people, buildings, health systems, crops and ecosystems.
In such a scenario, adaptation cannot be limited to reacting when a red alert is issued. Homes, cities and workplaces need to be prepared for prolonged periods of heat; shade and urban vegetation need to increase; access to safe cooling must improve; vulnerable people need protection; and landscapes and soils need to be managed so that they retain more water and continue functioning under extreme conditions.
More than 35,000: a provisional figure, not a final toll
The figure of more than 35,000 excess deaths published at the end of August should be understood as a provisional snapshot, not as a harmonised epidemiological total for Europe as a whole. It comes from a compilation of national datasets that use different methods and, at that point, did not yet include every episode in August.
Since then, some countries have updated their estimates. Germany raised its estimate to around 16,000 heat-related deaths; France incorporated later episodes in July and August; and other national systems continue to consolidate their records. A definitive European total will take time to establish and should not be produced simply by adding figures calculated using different methodologies.
What can already be said is that the summer of 2026 has shown with exceptional clarity how extreme heat can simultaneously become a crisis of public health, water, soil, agriculture, biodiversity and wildfire risk.
One idea to remember
| “Extreme heat is no longer an isolated episode: it is an environmental pressure linking human health, water, vegetation, soil and territorial resilience.” |
Methodological note
Not all of these figures mean the same thing. Germany estimates heat-related mortality using dedicated models; Spain calculates temperature-attributable mortality through MoMo; France reports all-cause excess mortality observed during the days and areas affected by heatwaves; and the United Kingdom estimates deaths associated with specific heat episodes. These figures are therefore useful for assessing the scale of the impact, but they should not be treated as a single, directly comparable European statistic.
Main references
- AEMET — Summer 2026 climate assessment (21 September 2026)
- Robert Koch Institute — Heat-related mortality in Germany
- Santé publique France — Excess mortality, 17 June–2 July
- Santé publique France — Excess mortality, 27 July–20 August
- Météo-France — Summer 2026 climate assessment
- UK Health Security Agency — 2,877 heat-associated deaths during the May and June episodes
- Copernicus Climate Change Service — August and summer 2026 temperatures
- World Weather Attribution — European heatwaves in June 2026
- World Weather Attribution — Wildfire conditions in France and Spain
- Joint Research Centre / EFFIS — Current wildfire situation in Europe
- The Guardian — Provisional compilation of >35,000 excess deaths (25 August 2026)
- RTVE / MoMo data — 5,091 heat-attributable deaths in Spain
