Germany's Robert Koch Institute estimated that 15,800 people died from heat-related causes during summer 2026, the highest seasonal figure in the decade that the national public health institute has monitored such mortality. The assessment followed repeated heatwaves that sent temperatures above 40C in parts of the country.
The toll is a statistical estimate rather than a count of death certificates listing heat as the cause. The institute calculates excess mortality by comparing deaths during hot summer weeks with expected mortality during periods without significant heat. That method is intended to capture both direct consequences, such as heatstroke, and deaths in which high temperatures worsen an existing illness.
People older than 75 were the most severely affected group, the institute said. Approximately 9,600 heat-related deaths were attributed to one week of extreme temperatures in late June. A further 4,000 were estimated between late July and mid-August. The supplied report did not provide a detailed breakdown for the remainder of the seasonal total.
Extreme heat can place additional strain on the heart, lungs and kidneys, making cardiovascular, respiratory and renal conditions more dangerous. Older adults are at heightened risk because underlying health problems are more common and the body's ability to regulate temperature can decline with age.
The estimated 2026 total substantially exceeded the institute's previous record of roughly 8,900 heat-related deaths in 2018. A separate medical-journal report had estimated about 10,000 such deaths in Germany in 1994, before the institute's current decade-long monitoring period.
Germany's experience formed part of a wider hot and dry European summer. Across the continent, extreme temperatures were associated with higher mortality, while dry conditions contributed to wildfires, agricultural damage and low water levels in major rivers.
The report also compared the estimated 9,600 deaths during the late-June heatwave with 6,045 reported Covid-19 deaths in Germany's worst week of the pandemic. The heat estimate was about 59% higher, but the figures were produced differently and should not be treated as directly equivalent: one was modelled from overall mortality, while the other consisted of reported deaths attributed to an infectious disease.
The assessment highlights why heat mortality can be difficult to see in real time. Many deaths occur through the worsening of chronic disease rather than an immediately identifiable heat injury. As a result, the final burden becomes clearer through population-level analysis after temperatures and mortality have been measured together. The model therefore estimates deaths associated with periods of excessive heat across the population; it does not establish the precise role of temperature in every individual case. Comparisons between seasons also depend on applying a consistent statistical approach to mortality and weather data.
