Key Points

• In late May, France experienced a heat wave. This heat wave occurred early, before the seasonal monitoring system had been activated.
• Météo-France issued a yellow heat wave advisory for Finistère on Sunday, May 24, followed by Ille-et-Vilaine and Morbihan the next day, Monday, May 25. From May 26 to 28, all four departments in Brittany were under an orange heat wave advisory. On Friday, May 29, Ille-et-Vilaine and Morbihan remained under an orange heat wave alert, while Côtes d’Armor and Finistère were under a yellow alert. On May 30, only Ille-et-Vilaine remained under a yellow heat wave alert. All departments were back under a green alert on May 31.
• A regional analysis of hospital emergency room visits and calls to SOS Médecins indicates an increase in the composite health indicator iCanicule1 starting on May 21, with a more significant rise during the heatwave from May 25 to 29. This trend shows higher fluctuations than those observed in previous seasons during heat waves. The trends in the monitored indicators were consistent across all departments.
• Since the end of the heatwave, a decline in the iCanicule composite health indicator has been observed across the entire region of Brittany.
• Heat poses a health risk to the entire population. The observed health impacts underscore the importance of implementing preventive measures to mitigate the effects of heat.