An exceptionally early and powerful heat wave that swept across Europe this summer appears to have triggered a dramatic surge in deaths, with emerging data suggesting that well over 10,000 more people died during the peak of the heat than would normally have been expected.
Researchers track what is known as “excess mortality” — the gap between the number of deaths that would typically occur and the actual number recorded. That figure spiked sharply in late June, when portions of Europe endured record-breaking temperatures. Experts warn that the full picture takes time to develop, and that many heat-related deaths are never officially classified as such. A heart attack, for instance — which can be brought on by extreme heat, particularly in elderly individuals or those with pre-existing health conditions — may simply be recorded on a death certificate as a heart attack, with no mention of heat.
The alarming toll marks a troubling start to the summer season. Heat waves have claimed thousands of lives across Europe in recent years, though 2003 remains the deadliest on record, with roughly 70,000 deaths attributed to heat that year. Scientists note that the growing frequency and severity of heat waves are being driven by climate change, which results from the burning of fossil fuels such as coal, oil, and natural gas.
The EuroMOMO mortality monitoring network, which collects data from approximately two dozen countries, estimated 14,260 excess deaths from all causes during the week that ended June 28. More than 12,000 of those deaths were among people aged 65 and older, out of a total of 84,583 deaths recorded that week. Death figures in the weeks before and after were significantly lower.
Lasse Vestergaard of Denmark’s Statens Serum Institut, which oversees EuroMOMO, explained that “we attribute this to the heat wave affecting quite a lot of countries in Europe, and we do that because there is no other obvious explanation that could explain such a high excess mortality happening at the moment.” He described such a sharp spike in a single week as “highly unusual.” While EuroMOMO does not release country-by-country figures, it identified France, Belgium, and Germany as having the highest rates of excess deaths.
Individual countries have also released their own estimates, though the methods and timeframes used vary. Here is a look at what different nations are reporting.
Germany’s disease control agency, the Robert Koch Institute, directly linked 6,830 deaths to heat through early July, with 6,470 of those victims being 65 or older. Temperatures in Germany hit their highest recorded levels in late June, reaching a peak of 41.7 degrees Celsius (107.06 Fahrenheit) on June 28, according to the German Weather Service.
In England and Wales, the national weather agency — Britain’s Met Office — estimates that approximately 2,700 people died from heat-related causes during heat waves in May and June. Around 550 of those deaths occurred in late May, with roughly 2,200 happening in late June. The country set national heat records for both May, at 35.1 Celsius (95.18 Fahrenheit), and June, which exceeded 37 Celsius (98.6 Fahrenheit).
France’s public health authority reported at least 2,000 more deaths during the week of June 22-28 compared to the previous week, when temperatures were already on the rise. France experienced its hottest days ever on June 24 and 25, when the Meteo France weather service said its national thermal indicator — an average of daily temperatures from 30 weather stations — reached 30 Celsius (86 Fahrenheit). Over 40 percent of the country saw peak temperatures exceeding 40 Celsius (104 Fahrenheit).
In Spain, the Carlos III Health Institute, an official government monitoring agency, attributed an estimated 937 deaths in June to excess heat. The AEMET weather agency reported that last month was Spain’s second-hottest June on record, with temperatures running 3.2 Celsius (5.8 Fahrenheit) above the monthly average. A five-day heat wave pushed temperatures well above 40 Celsius (104 Fahrenheit) on a regular basis.
Belgium recorded 1,747 deaths above the expected level during the heat wave that lasted from June 18 to July 1, according to Sciensano, the country’s public health institute. The agency noted that “a certain excess mortality is expected during heat waves, as during waves of cold weather and flu epidemics,” but added that “the heatwave of June 2026 is distinguished by its exceptional breadth.” Temperatures at the height of the heat wave reached 35.5 Celsius (95.9 Fahrenheit) on June 26, according to the IRM weather institute.
The Netherlands saw approximately 480 more deaths than expected during the June heat wave, according to its public health service. The increase in deaths was most pronounced in the eastern and southern parts of the country, where temperatures climbed the highest. The Dutch weather service recorded a June temperature record of 36.8 degrees Celsius (98.24 Fahrenheit) — more than a full degree Celsius (1.8 Fahrenheit) above the previous record, which had stood since 1947.
