The heatwave that struck France from June 17 to July 2 resulted in record excess mortality since 2003, including among young people, although two-thirds of the deaths affected the elderly. according to a preliminary assessment.
Thus, 5,764 excess deaths were recorded during this episode of extreme heat, half of them in three days from June 25 to 27, the Public Health France agency indicated on Wednesday, July 22.
This surge in all-cause mortality – which cannot yet be definitively attributed to the heat – has been observed for " all age groups from 15 years old", with a " marked increase from age 45", what experts consider" unpublished“.
Heatwave deaths: a political issue
The death toll figures, which are gradually becoming more precise over the weeks, are fueling a bitter political battle, with the government being accused by the opposition of being unprepared for the consequences of global warming.
Environmentalists, in particular, had anticipated a death toll of 10,000 for the June heatwave, a figure immediately denied by the Prime Minister's office. The government has strived to avoid any comparison with the 2003 heatwave, which traumatized France by causing 15,000 deaths, many of them in nursing homes.
Eventually, " It is noted that despite the extremely intense episode in June (...), the number of excess deaths observed is much lower "In 2003," the office of Health Minister Stéphanie Rist reiterated at a press briefing on Wednesday. However, the 2003 heatwave lasted three weeks, compared to 16 days this time.
How does Public Health France measure the impact on mortality?
The week after the end of the heatwave, the agency publishes an initial estimate of all-cause mortality. This estimate is based on electronic death certificates, which represent approximately 60% of all deaths registered nationwide.
However, this coverage varies across regions and, especially, depending on the place of death. Indeed, only about 25% of deaths occurring at home are recorded by this system, compared to 45% of deaths in nursing homes and nearly 80% of deaths occurring in hospitals.
A second dataset for a more precise measurement
Three weeks after the end of each heat wave, the public agency publishes a second set of data, based on a sample of approximately 5,000 civil registry offices that automatically transmit their information to INSEE. This network covers nearly 84% of the mortality recorded nationally.
Based on this data, Public Health France estimates the number of additional deaths that occurred during heatwave episodes by comparing the observed mortality from all causes to a reference mortality.
To establish this estimate, the agency relies on a statistical model developed within the framework of the European EuroMOMO project. This model takes into account historical data from the last six years, the general trend in mortality, seasonal variations, and excludes periods marked by exceptional events.
This is the data that was published on Wednesday, July 22nd, for the June heatwave. However, it should be interpreted with caution, as the data transmitted by INSEE may still change for several weeks before being definitively consolidated.
These estimates therefore do not allow us to precisely identify the deaths directly attributable to the heat, but measure the excess mortality that occurred during the heat wave.
A couple travels in the middle of a heatwave in Bordeaux, June 25, 2026. Credit: AFP/Archives – Christophe ARCHAMBAULT
The true human toll will be revealed several months after the summer.
The consolidated report of all available data is published by Public Health France at the end of the summer monitoring period. It includes the overall impact of heat on health, the final estimate of excess mortality from all causes, the number of deaths attributable to heat, and the count of fatal workplace accidents that may be linked to high temperatures.
This figure is generally considered a conservative estimate, however, as a direct link to heat is not always identifiable. When a person dies several hours or days after exposure to intense heat, particularly in the workplace, the death may not be attributable to the heat or their work.
This final assessment nevertheless allows for a better measurement of the true impact of heat waves on the health of the French population. It may reveal a much higher death toll than the figures recorded solely during heat waves, because it takes into account heat-related deaths throughout the entire summer period, and not just during temperature peaks.
In 2025, for example, 1,900 deaths were attributed to heat during the three heatwave episodes, but an additional 5,700 deaths were recorded over the entire surveillance period by Public Health France, from June 1 to September 30.
However, accurately identifying the causes of death requires in-depth analyses, which can take several years.
Read also Our mental health is affected by heat waves.
A unique episode, but difficult to compare to 2003
Guillaume Boulanger, an expert at Public Health France, urges caution when comparing this to the 2003 heatwave. Twenty years separate the two events, and the data available at the time was less comprehensive. Since then, the healthcare system has evolved considerably, and the demographic structure of the French population has also changed, with a larger proportion of elderly people.
Moreover, due to its early arrival and exceptional duration, the heatwave of June 2026 constitutes an unprecedented event. It affected 98.5% of the metropolitan population, in 92 departments, at a time when school and professional activities were still largely underway, emphasizes Public Health France.
Seniors are paying the heaviest price, but those aged 45-64 are particularly affected.
Two-thirds of the excess mortality recorded during the heatwave episode concerns people aged 75 and over, who remain the main victims due to their greater vulnerability and often more fragile state of health.
But the heat wave also hit the 45-64 age group particularly hard. This age group recorded 979 additional deaths, an increase of 55 per 100,000 compared to the expected mortality rate for this time of year, barring any exceptional events.
These figures remain provisional, pending the final tally expected in the fall on deaths "attributable" to the heat. Public Health France estimates that the toll will "likely" rise further, as some deaths currently classified as normal mortality may ultimately be linked to the heatwave.
The heatwave is hitting the Île-de-France region hard
The agency highlights the "very strong" health impact of this climatic event, except in Corsica, Occitanie and Provence-Alpes-Côte-d'Azur, which were slightly less exposed.
In Île-de-France, which was particularly hard hit, mortality doubled compared to its normal level, with 1,999 deaths. This was followed by Grand Est, Pays-de-la-Loire and Centre-Val-de-Loire, with 635, 553 and 511 excess deaths respectively.
Deaths "have increased in all types of places": hospitals, nursing homes, retirement homes, and "particularly at home," Mr. Boulanger pointed out.
In addition to the June figures, there are 300 excess deaths "from all causes" recorded during the first heat wave of this year, from May 24 to 28, which was earlier but shorter and less intense.
Read also Heatwave: Europeans massively exposed to dangerous levels of ozone
Beyond the days of extreme heat, the heat kills throughout the summer.
In addition, the country followed up in mid-July with a third episode, while repeated exposure to heat waves exhausts organisms, particularly weakening vulnerable populations (children, the elderly, those in precarious situations, chronically ill people…), according to specialists.
If the heatwave days only represent " 4 to 5% on summer days, they account for 30% of heat-related deaths "during the summer period. But " Exposure to heat can have an impact on mortality throughout the summer." concludes Guillaume Boulanger.
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