France recorded its hottest night in history between Wednesday, June 24, and Thursday, June 25, 2026, with a national average of 22°C [1].
This record indicates a dangerous trend in nocturnal cooling, which is critical for human health and infrastructure. When nighttime temperatures fail to drop, the body and environment cannot recover from daytime heat, intensifying the impact of the current heatwave.
The national thermal indicator for minimum temperatures, which averages data from 30 reference stations, reached the provisional value of 22°C [1]. A national forecaster from Météo-France said this figure represents a new absolute record [1]. This surpasses the previous record of 21.6°C, which was set during the night of Monday, June 22 [2].
The extreme heat follows what has been identified as the hottest day ever recorded in France on June 24, 2026 [5]. The persistence of this heatwave has forced authorities to issue high-level warnings across the territory. Reports on the scale of the emergency vary, with some sources stating that 72 departments are under red vigilance this Thursday [3], while others cite 58 departments [4].
Officials said the current situation is "unprecedented" [3]. The red vigilance level is the highest alert tier used by French meteorological services to warn the public of extreme weather risks. The heatwave has pushed minimum temperatures to levels that challenge traditional urban cooling strategies, leaving millions of citizens exposed to prolonged heat stress without nocturnal relief.
Météo-France continues to monitor the 30 reference stations to finalize the thermal index. The agency said the 22°C mark is a provisional value but confirms the previous record has been exceeded [1, 2].
“The national thermal indicator for minimum temperatures... affiche une valeur provisoire de 22 °C, nouveau record absolu.”
The breaking of a national nocturnal record shortly after the hottest day in French history suggests a compounding heat effect. When minimum temperatures rise, it prevents the 'diurnal cooling' necessary to lower the temperature of buildings and pavement, creating a feedback loop that makes subsequent days even hotter and increases the risk of heat-related mortality.
