Key Points 

• This weekly bulletin presents the latest epidemiological monitoring of the heat wave that began on June 17, 2026, covering the period from June 23, 2026, to June 29, 2026.
• As of June 23, 2026, all eight departments in the Île-de-France region had been under a red heatwave alert since June 20, 2026. On Sunday, June 28, 2026, all departments in the Île-de-France region were downgraded from red to orange alert, and on Monday, June 29, 2026, from orange to yellow alert. On Tuesday, June 30, 2026, at 6:00 a.m., all departments were downgraded to the green level.
• A regional analysis of emergency care utilization shows an increase in visits and in the proportion of hospitalizations following emergency room visits for the iCanicule composite health indicator (which includes hyperthermia, dehydration, and hyponatremia). There was also an increase in emergency department visits for all causes (among those aged 75 and older) and in hospitalizations following emergency department visits for all causes (among those aged 75 and older and all age groups).
• Regional analysis of SOS Médecins consultations also indicates an increase in the composite health indicator iCanicule (heatstroke, dehydration) throughout the entire episode. There was also an increase in SOS Médecins interventions (no data available for Val-d’Oise) for all causes during the same period.
• This trend falls within the expected fluctuations given the current weather conditions and is observable across the region as a whole.