Key Points 

• Since May 26, 17 departments have been placed under an orange heat wave alert in 5 regions (Brittany, Île-de-France, Normandy, Nouvelle-Aquitaine, and Pays de la Loire), representing 26% of the resident French population affected by at least one day of an orange heatwave alert. The orange heatwave alert ended on May 30.
• This episode is unprecedented, historic, and exceptional for the month of May, according to Météo France. According to a European study, the temperatures observed during this heatwave in Western Europe are attributable to climate change.
• An increase in healthcare visits for heat-related conditions (hyperthermia, dehydration, and hyponatremia) and fainting spells was observed nationwide throughout the duration of the episode and across all age groups. The number of emergency care visits due to heat-related issues began to rise on May 22, peaking on May 26 (411 emergency room visits and 253 SOS Médecins consultations). The number of SOS Médecins consultations for May 26 approaches the peak numbers observed in previous summers (around 300 consultations in late June/early July during the heatwaves of the summers of 2025 and 2019).
• The number of hospitalizations following emergency room visits due to iCanicule began to rise on May 22 (more than 100 daily hospitalizations) and reached a peak in healthcare utilization on May 29 (231 hospitalizations). Of these hospitalizations, 49 have been in intensive care/resuscitation units since May 22.
• Hyperthermia and heatstroke primarily affect people under 15 and those aged 15–44. Dehydration and hyponatremia primarily affect those aged 75 and older.
• These observations regarding emergency care utilization and the early onset of this episode—which occurred during a busy period of school and work activities—highlight greater impacts than those typically observed among people under 15 and those aged 15 to 45. This finding underscores the particular importance of strengthening prevention efforts and adapting the environments frequented by these populations, in addition to existing measures.