German institute estimates 5,100 heat-related deaths in June heatwave

Some 5,100 people died in Germany from heat-related causes during June's heatwave, according to estimates by the Robert Koch Institute (RKI).

The country's public health institute released the estimate on Thursday in its latest weekly report on heat-related mortality. 

The figures already exceed the annual average of about 2,900 heat-related deaths recorded between 2023 and 2025, the RKI reported.

The institute estimated that heat-related deaths increased by 4,310 during the week of June 22–28, when Germany experienced its most intense heat. Temperatures climbed above 40 degrees Celsius in parts of the country during that period.

For the period from April through June 21, the RKI had estimated 810 heat-related deaths. However, an RKI spokeswoman said that virtually all of these deaths occurred during the week of June 15-21.

Elderly most at risk

Older people were by far the hardest hit. Around 2,950 of the estimated deaths by June 28 occurred among those aged 85 and older. The figure was about 1,320 among those aged 75 to 84, around 550 among those aged 65 to 74, and approximately 300 among people under 65.

The RKI said the overall impact of the heat may have been even greater. 

Germany's Federal Statistical Office recorded around 6,800 excess deaths during the week of June 22–28, although the two figures were calculated using different methods.

The extreme conditions were also linked to infrastructure damage and dozens of swimming-related deaths. Buckled road surfaces led to the temporary closure of motorways, while rail services were disrupted in some areas due to heat-related damage.

Record-breaking temperatures

According to the German Weather Service (DWD), June 2026 was the country's second-warmest June since records began, after 2019. 

The late-June heatwave brought temperatures above 41 degrees Celsius, while 46 weather stations recorded temperatures exceeding 40 degrees on June 27.

The RKI estimates heat-related mortality using statistical models because heat is often not listed as the underlying cause of death, particularly when it worsens existing health conditions.

"In some cases, such as heatstroke, exposure to extreme heat leads directly to death," the RKI said. 

More often, however, heat contributes to deaths by aggravating pre-existing illnesses, meaning it is not usually recorded as the underlying cause on death certificates.

The institute noted that its estimate for the period from April through June 28 carries a wide margin of uncertainty, ranging from 4,410 to 5,850 heat-related deaths.