Key Points 

• A prolonged, intense heat wave, with a severity level close to or equivalent to that of 2003, affected France from June 18 to 28, 2026.
• Météo-France issued a yellow heat wave alert for Ille-et-Vilaine on Thursday, June 18. On Sunday, June 21, all departments in Brittany were placed under an orange heat wave alert. From Monday, June 22, through Thursday, June 25, all departments in Brittany were under a red heat wave alert. On Friday, June 26, Morbihan was downgraded to an orange alert, while Finistère and Côtes d’Armor were downgraded to a yellow alert. On Saturday, June 27, Ille-et-Vilaine was downgraded to an orange heat wave alert. On Sunday, June 28, all departments in Brittany were under a green heat wave alert, marking the end of the heat wave episode for the region.
• A regional analysis of emergency care utilization shows a very sharp increase in the iCanicule composite health indicator throughout the entire episode from June 21 to 27. The number of emergency room visits and SOS Médecins calls for this indicator, as well as the associated activity shares, reached very high, unprecedented levels—unseen since the monitoring system was established.
• People aged 75 and older, as well as the departments of Ille-et-Vilaine, Morbihan, and Finistère, were the hardest hit.