Météo France, the national meteorological service, issues heatwave (canicule) vigilance alerts based on a combination of meteorological thresholds and health impact criteria. The system uses a four-level color-coded scale: green (no vigilance), yellow (moderate), orange (high), and red (exceptional).
For an orange or red alert, Météo France considers both daytime maximum temperatures and nighttime minimum temperatures over at least three consecutive days, with regional variations. For example, in Paris, the threshold for a red alert is a maximum of 40°C and a minimum of 24°C, while in Marseille, it is 38°C and 23°C. These thresholds are defined in collaboration with Santé publique France.
As of May 24, 2026, no exceptional heatwave alert has been issued for the entire country, but localized alerts may be in effect. The system was notably activated during the July 2019 heatwave, when red alerts were declared for several departments.
