Summer 2026 was the warmest on record for western Europe. The European climate service Copernicus puts the mean temperature from June to August at 21.69 degrees Celsius, 2.54 degrees above the average for the years 1991 to 2020. The long-standing record from 2003 has been beaten.
For Europe as a whole it was the third-warmest summer in the series. The record therefore does not apply evenly across the continent, but above all to the west. What stood out there was not a single peak value but the duration: from late May onwards several heatwaves followed one another, unusually early and unusually stubborn. For June and July together Copernicus reports 21.62 degrees, 2.79 degrees above the average and above the previous record from 2022.
The situation was carried by an omega block: a stable high-pressure area, flanked by two lows, stays in place for days. Hot, dry air from North Africa is held underneath it and cannot move away. Western and central Europe were also markedly drier than usual, so heat and drought reinforced each other. The research group World Weather Attribution concludes that the June heat would have been practically impossible without human-caused warming.
At a glance
21.69 °C
Summer mean in western Europe
+2.54 °C
above the 1991 to 2020 average
2003
previous record summer
Why the death tolls diverge
The casualty figures in circulation differ by a multiple. That is not because anyone is calculating wrongly, but because different things are being counted. Heat deaths are almost never recorded directly; a death certificate usually says heart failure, kidney failure or a lung disease. What is determined instead is excess mortality: the actual deaths in a period are compared with the statistically expected number, and the difference is attributed to the heat.
Heat deaths are not counted, they are estimated. That is why there is not one figure but several.
— TerraTally · Climate desk
Depending on method, period and the countries included, the results differ widely. For Germany, the Robert Koch Institute reports excess mortality of around 19,400 cases from mid-May to the end of August, with an uncertainty range of 14,700 to 23,700. About 16,300 of those are attributed to the heat, some 9,600 of them in the last week of June alone. For that same week the Federal Statistical Office recorded 32 percent more deaths than the average of the four preceding years. Across Europe the EuroMomo monitoring network reported more than 32,000 excess deaths between mid-July and mid-August. A final, peer-reviewed total for summer 2026 is still pending; for summer 2024 such an analysis arrived at around 62,700 heat-related deaths in Europe.
What holds up is therefore less a single figure than the pattern: those affected are mostly old, often already ill, and they mostly die not in the street but in flats that do not cool down at night. The heat also hit infrastructure: road surfaces and rails buckled, closures and cancelled trains followed, and drought and heat favoured wildfires.
Against hardly any weather extreme is as much known as against heat, and most of it is simple. During a wave, heat action plans with clear trigger thresholds work: warnings, outreach for older people living alone, longer opening hours for cool public spaces, drinking water points, adjusted outdoor working hours and hospitals ready for extra admissions. France introduced such plans after the summer of 2003.
On the building, the night decides. If a flat no longer cools down, the recovery phase is missing, and that is what people die of. External shading works considerably better than internal shading, and to that come cross-ventilation during the cool hours, light-coloured roofs and façades, and insulation that carries in summer as well as in winter. In the city, what helps is whatever keeps heat from being stored at all: trees shade and cool by evaporation, unsealed surfaces and water take heat out of a district, and ventilation corridors bring cool night air into the centre.
The remarkable thing about this list is how little of it is high technology. The difference between a heatwave survived and a lethal one often comes down to a shutter mounted outside rather than inside, a phone call to the neighbour on the fourth floor and a tree in front of the window.
Figures as of 15 September 2026. Excess mortality is modelled and revised afterwards.