Key Points

• The summer of 2018 was marked by a heat wave lasting from July 24 to August 8. At the peak of this episode, on August 6, 67 departments were under an orange alert, and 18 under a yellow alert, representing 70% of the metropolitan population. Nationally, this heat wave exhibited climatic characteristics comparable to those of late June 2015, more intense and severe than in 2006 but far from the characteristics of August 2003. More localized heat waves were also observed in early July and mid-August.

• From July 24 to August 11 (a period extended by 3 days to allow for the estimation of delayed impacts), there were 5,676 emergency room visits and 1,963 SOS Médecins consultations for heat-related conditions. 58% of these emergency room visits resulted in hospitalization. While the impact is greater among those over 75, all age groups are affected.

• During periods when alert thresholds were exceeded¹ and across all affected departments, 1,480 [958: 1,958] excess deaths were observed, representing an excess mortality rate of 15.0% [9.2: 20.8%]. People aged 75 and older accounted for more than half of the deaths, 931 [543: 1,277]. However, the greatest relative impact was observed among those aged 65–74 (+26%).

• The excess mortality is similar to that of the summer of 2015, when the characteristics of the heatwave were similar to those of 2018.

• During the period from July 24 to August 11, four cases of fatal workplace accidents potentially linked to heat were reported to Santé publique France by the Occupational Health Inspection.

• Prior to the summer of 2018, 778,747 prevention documents were distributed in France. A poster specifically for workers was also distributed in 10,000 copies in the prevention magazine of the Professional Prevention Organization for the Building and Public Works Sector. TV and radio spots were broadcast from July 31 to August 9 as part of the Ministry of Health’s media campaign.

• The health impacts of heat observed during the summer are not limited to the period from July 24 to August 8, as two-thirds of emergency room visits for heat-related illnesses occurred outside of this period.

• Prevention of the heat’s impact must be planned for the entire summer period and intensified during heat waves.