Spain has witnessed a staggering 87.6% increase in heat-related fatalities between May 16 and September 30, with the health ministry reporting 3,832 deaths. This sharp rise, compared to the same period in 2024, underscores the devastating impact of extreme temperatures on vulnerable populations. Nearly two-thirds of the victims were aged over 85, while almost 96% were above 65, highlighting the heightened risk for older adults. The figures, derived from Spain’s Mortality Monitoring System (MoMo), utilize statistical models to estimate deaths linked to heatwaves. MoMo tracks daily mortality trends and incorporates external factors, such as weather data from the national meteorological agency AEMET, to identify potential causes of mortality spikes. Although MoMo cannot definitively attribute deaths to heat, it provides the most reliable approximation of fatalities where high temperatures likely played a decisive role. This year, Spain endured its hottest summer since records began in 1961, with an average temperature of 24.2°C. Heatwaves persisted for 33 of the 90 summer days, including a 16-day event in August that triggered wildfires, claiming four lives and devastating vast areas of land. Scientists have repeatedly warned that human-induced climate change is intensifying global weather extremes. Notably, nine of Spain’s 10 hottest summers since 1961 have occurred in the 21st century. Similar trends were observed in Britain, Japan, and South Korea, which also experienced their hottest summers on record this year.