New insights on Spain’s summer heat and mortality
The unusually high temperatures Spain endured this summer led to a total of more than 12,000 deaths between June and August, with over 5,300 attributed directly to extreme heat. This fresh calculation shows heat-related deaths were higher than initial estimates from the Ministry of Health, indicating that heat may have accounted for more than half of the excess deaths observed during those months.
Experts from the Supreme Council for Scientific Research (CSIC), the University of Valencia, and the Spanish Consortium for Epidemiology and Public Health Research (CIBERESP) reached this conclusion after further analysis of mortality data from the three-month period. The study highlights how successive heatwaves drove the elevated death toll across the country.
Midsummer under the heat waves
State meteorological records show that the summer closed with heatwave conditions on 42 days, nearly half of the season. These 42 days vastly exceed the long-term average for heatwaves, which stood at about six days in the period 1981 to 2010. Comparing to the more recent decade 2011 to 2020, the number of heatwave days in the summer rose to 14, more than twice the prior decade’s average and approaching a record. A 29-day heatwave in 2015 remains a benchmark. The summer of 2022 was the hottest since the 1960s.
Images from the period show the toll of heat in mortality data. The Carlos III Health Institute’s MoMo system detected an excess of about 21,471 deaths during these months, with the contemporary model attributing around 12,054 deaths to heat, of which 5,316 occurred on days when temperatures exceeded 26.5ºC and were thus considered excessive.
Heat-related fatalities were especially amplified in June, July, and August. June logged 1,798 heat deaths, July 2,588, and August 2,356. The period from July 10 to July 25, followed by another heatwave from July 31 to August 13, intensified the surge. July tallied 3,204 excess deaths, while August accounted for 1,406. The pattern suggests that prolonged heat spread across much of the country in July, a shift noted by researchers as critical in understanding the mortality spike.
One of the researchers remarks that July’s amplified lethality stems from the widespread reach of the heatwave, not from a single region alone. This broader exposure helps explain the striking jump in deaths during that month.
As the data accumulate, it becomes clear that extreme heat has a far greater impact on mortality than previously understood. Comparisons with earlier years show a dramatic rise: extreme-heat deaths in the range of a few hundred or near a thousand were common in 2020 or 2021, but the current summer’s figure marks a sharp departure. The results also point to growing inequality in vulnerability, with those most exposed to heat and with limited resources bearing the greatest risk of death from extreme temperatures.
More deaths than the ministry initially estimated
The new data reveal that heat accounted for more than half of the excess mortalities this summer, far above the roughly one‑fifth projected by the health ministry. Some experts argue that the discrepancy stems from outdated measurement methods used in official reports. Several scientists advocate revising how heat-attributable mortality is calculated in national statistics to better reflect real-world impact.
Researchers emphasize that heat danger extends beyond the familiar image of heatstroke. In many cases, deaths are linked to heart and respiratory illnesses aggravated by high temperatures, underscoring the need for public awareness and preventive measures during heat events.
The findings align with broader health research that documents a direct link between extreme heat and heightened cardiovascular risk. This corroboration reinforces the urgency of adapting public health responses to rising temperatures.
The outlook for the future
Experts caution that the current situation is not a one-off event. The IPCC’s sixth assessment report suggests that extreme heat waves may become more common in the coming years for the peninsula. Spain already faces climate-related health risks and, today, a meaningful share of heat-related deaths is tied to climate warming.
Still, there is room for adaptation and mitigation. Researchers advocate practical steps such as adjusting work hours during peak heat, protecting outdoor workers, and improving built environments. In a broader strategy, they propose climate shelters in cities—places like large malls where people can find cooler temperatures—and expanding green spaces. Research indicates that a 20% increase in urban green spaces could reduce temperatures by roughly 9%, suggesting a possible link between environmental design and health protection, even though causality remains to be fully proven.
For context, the broader medical literature supports these concerns. Publications from cardiovascular health authorities reinforce the observed relationship between extreme heat and mortality from heart disease and related conditions.
In closing, the probability of repeated heat-driven mortality events remains high. The goal is to reduce vulnerability through smarter planning, stronger community resources, and policies that prioritize health during heat waves, all while acknowledging that climate change is reshaping risk profiles across Spain and beyond. The dialogue continues as scientists and policymakers search for effective, evidence-based solutions that protect public health in a warming world.
Notes for readers: ongoing research and official assessments inform these conclusions. Attribution is provided to the scientific teams and major health organizations involved in these analyses.