Each heat wave seems more intense than the last. This Monday, June 22, 49 departments were placed on red heatwave vigilance and 40 others on orange vigilance. According to Sophie Voirin, director of Météo France, “the heatwave we are experiencing should be similar to those of July 2019 and August 2003 in terms of temperature intensity”.
These two episodes now constitute historical benchmarks in terms of extreme heat in France. The heatwave of summer 2003 remains the reference event, both in terms of its duration and its intensity and its human toll: nearly 15,000 deaths were attributed to it.
Between August 2 and 17, 2003, France experienced two weeks of exceptional heat. The national thermal indicator, which corresponds to the average of minimum and maximum temperatures observed in several cities, had reached 29.3°C. The severity of the episode, calculated from an index developed by Météo France to compare heat waves, rose to 58.5, a level never equaled since records began in 1947.
Stifling nights
That summer, temperatures reached unprecedented levels: 41.1°C in Bergerac on August 4, 42.6°C in Orange on August 12. At the origin of this situation, a powerful heat dome had trapped the country under an extremely hot and dry air mass, with a peak observed around August 5.
What made the episode so trying was not only the heat during the day, but also the nights which remained stifling. In many cities, the thermometer had not dropped below 25°C before daybreak. At the time, France was not prepared for such a phenomenon: air conditioning was not widespread, warning systems were limited and the health risks were still poorly known to the general public. It was following this disaster that Météo France’s heatwave vigilance system was created the following summer.
Sixteen years later, during the 2019 heatwave, the country has more tools to deal with it. Alert procedures are well-established, communities have implemented action plans and prevention messages are widely disseminated. Shorter than that of 2003, this heat wave will nevertheless remain one of absolute records.
2019, year of records
On June 27, 2019, the national average temperature stood at 27.9°C, or 8.6°C above seasonal norms, a record for the month of June. Faced with this exceptional episode, Météo France is triggering heat wave red vigilance for the first time in its history. The next day, the thermometer reached 46°C in Vérargues, in Hérault, the highest temperature ever measured in France.
A second heat wave hits the country from July 21 to 26. The national average temperature then reaches 29.4°C. On July 25, the intensity of the heat observed across the country was comparable to that recorded on August 5, 2003. On the night of July 24 to 25, the national average temperature did not fall below 21.4°C, establishing the hottest night ever observed in France since measurements began.
The year 2026 could in turn bring its share of records. As early as May, a first heat wave led to the triggering of heatwave alert, a first this early since the creation of the system. The current episode already sets a record for its scale, with 89 departments placed on red or orange vigilance. According to Météo France, the night from Sunday to Monday was “exceptionally hot”, with minimum temperatures of 24.8°C in Tours and 24.6°C in Poitiers.
