From May to July 2026, the death toll is double that of last year, and experts warn that heatwaves are no longer a seasonal nuisance but a public health emergency requiring mobilization of all resources.
Spain recorded 3,096 deaths linked to excessive heat in the first three months of the 2026 summer season, nearly matching the worst result of the past decade. For comparison, the same period in 2025 saw 1,481 deaths, while the 2022 record stood at 3,102, according to data from the Daily Mortality Monitoring System (MoMo) at the Carlos III Health Institute.
The figures suggest that the total summer toll will surpass last year's 3,832 deaths and could break the record 4,792 deaths from 2022. The deadliest summer of the century remains 2003 with 6,534 deaths, of which 4,363 occurred in August alone, during one of the longest heatwaves lasting 16 days, according to the State Meteorological Agency Aemet.
As early as May, with unusually high temperatures, 123 deaths were recorded, more than double the 57 in 2022. June saw 937 deaths, compared to 407 in 2025 and 828 in 2022. July, with 2,036 deaths, was slightly below the 2,217 in 2022, but the cumulative effect of earlier months brought the total in line with the worst year of the decade.
The hardest-hit regions are Catalonia with 676 deaths, the Basque Country with 344, and Andalusia with 335. The Balearic Islands recorded no heat-related deaths. The highest temperature in June was measured in Lleida (42.9°C) and Bilbao (42.7°C), according to Aemet data.
The Ministry of Health activated the National Plan for Preventive Measures against the Effects of Excessive Temperatures on May 15, 2026. A series of heat episodes followed: the first wave began on June 21 and lasted four days, the second from July 5 to 9, the third from July 21 to 23, and the fourth began on July 29 and is expected to extend until August 2.
José Chen, researcher at ISGlobal and Lancet Countdown in Europe, emphasizes that "heat-related deaths are already matching or exceeding the number of deaths from influenza during winter, which requires a proportional response. They must be treated as a public health emergency, mobilizing resources from all sectors to respond adequately."
The number of tropical nights, those where temperatures do not drop below 20°C, has quadrupled compared to the 1980s in major Spanish cities. "Nighttime temperatures matter because people have no window for recovery from daytime heat," explains Chen, adding that prolonged exposure, both day and night, is a key factor in mortality.
"In Mediterranean coastal cities, this risk is usually amplified by humidity and the urban heat island effect, which can keep the warmest neighborhoods hot until late at night," warns Chen. Heat-related mortality, he argues, is not only driven by absolute temperature but also by the duration of exposure, physiology, and behavior of the population, as well as the level of infrastructure and urbanization.
Carlos Fluixá, member of the Editorial Board of the Therapeutic Guide of the Spanish Society of Family and Community Medicine (semFYC), notes that heat mortality is not explained solely by thermal stress. It rises dramatically when high temperatures "coincide with high levels of atmospheric pollution, especially ozone and particulate matter," and "these compound events have a much greater impact on mortality than each factor alone."
Julio Díaz, research professor and co-director of the Reference Unit on Climate Change, Health, and Urban Environment at the Carlos III Health Institute, estimates that 18% of deaths during this time of year stem from "the amplifying effects that heat has on pollution." Public health measures, he says, "must take into account the effects of pollution levels in large cities."
The most common profile of the deceased is "an elderly, frail person with chronic diseases, whose clinical condition decompensates over several days of intense heat," describes Fluixá. As many as 96% of deaths in July were among people over 65. In Spain, 30% of that population consumes five or more chronic medications annually, a share that rises to 45% in the 85-94 age group. Among the drugs that interfere with thermoregulation, Fluixá lists "diuretics, anticholinergics, neuroleptics, and antihypertensives."
"The European continent is warming twice as fast as the rest of the world," warns Chen. Yet there is evidence that adaptation measures work: according to Lancet Countdown data, without any adaptation, the number of heat-related deaths would be far higher, but thanks to measures such as better housing, behavioral changes, and improvements in healthcare, the actual death toll has been significantly reduced.
Chen stresses that populations are adapting to the climate, while Fluixá advocates for an integrated approach combining public health, healthcare, urban planning, and protection of vulnerable individuals. Concrete measures include strengthening primary and emergency care, increasing home monitoring of patients, and introducing specific protocols for heatstroke and dehydration.
Although the data comes from Spain, the trend of rapid warming in Europe and increasingly frequent extreme heat directly affects the entire Mediterranean, including Croatia. The Spanish example shows that without robust adaptation plans, from urban interventions to strengthening primary healthcare, the human and economic costs could become unsustainable.
