Spain has recorded 1,682 heat-attributable deaths since 1 May, according to the MoMo daily mortality monitoring system run by the Instituto de Salud Carlos III, a public health research body under Spain's science ministry. For residents, carers and older people, the immediate consequence is clear: the highest risks are falling on people aged over 75, while doctors say emergency departments and consultations are seeing more heat-related cases.

The deadliest recent spell was the second heatwave of the summer, which left 622 heat-attributable deaths in five days up to Thursday, including 138 on Thursday and 123 on Wednesday, according to reporting based on MoMo data. Earlier, the first heatwave between Sunday 20 June and Thursday 25 June was linked to 278 deaths, with the State Meteorological Agency, AEMET, citing very warm nights across large parts of the country.

June was the worst since 2017

MoMo estimates that 937 deaths were attributable to high temperatures in June. That makes it the deadliest June since 2017, when around 1,000 heat-attributable deaths were recorded. The average for June over the 11 years of records cited in the source material is 249.

Heat impacts also arrived unusually early. In May, Spain recorded 101 heat-attributable deaths, the highest figure for that month since monitoring began in 2015, according to MoMo figures reported by Euronews from the monitoring data. That was 3.6 times the average May toll over the previous decade.

"MoMo is not a death register, nor does it define a number of people who have died: it calculates a daily estimate of excess mortality attributable to heat using historical mortality and temperature series through statistical techniques," the Instituto de Salud Carlos III says in its explanation of the system.

The institute says MoMo uses three data sources for its estimates:

  • daily deaths over the previous 10 years, excluding 2020 because of the Covid-19 pandemic
  • provincial temperature records from AEMET
  • population data by age group, sex and province from the INE national statistics institute

That means the figures are estimates of deaths potentially attributable to heat, not a count of confirmed heatstroke deaths. The system is updated daily and provides estimates by province, autonomous community, sex and age group.

Older people account for most deaths

Older age groups account for most of the June toll. Of the 937 heat-attributable deaths estimated for the month, 632 were among people aged over 85 and 220 were in the 75 to 84 age group.

Doctors say heat also raises risks for people with cardiovascular, kidney and respiratory conditions, diabetes and dementia, as well as babies and pregnant women, especially in the first trimester. Rosa Pérez, outreach coordinator at the Spanish Society of Emergency Medicine, said older people are more affected because they regulate body temperature less effectively.

For households, that matters because a large share of heat-related emergencies happen at home. Basic advice from emergency doctors includes keeping homes ventilated where possible, seeking cooled indoor spaces if they are not, drinking water even without feeling thirsty, avoiding outdoor activity in the hottest hours, and postponing physically demanding tasks such as DIY, gardening and cooking.

Hospitals and surgeries are seeing more pressure

Health professionals say the impact is not limited to deaths. Pérez said emergency departments have seen more work in recent years, particularly during major heatwaves and especially in large cities and coastal areas where populations increase during summer.

A report cited in the source material, Extreme Heat, Health at Risk, found that across Spain the probability of general hospital admission in summer rises by about 13.5% in association with extreme temperatures. In the paediatric population, the increase rises to 25.4%.

Separate research by ISGlobal, the Barcelona Institute for Global Health, based on 11 million emergency admissions in 48 Spanish provinces between 2006 and 2019, found especially sharp rises in some conditions during extreme heat. According to the source material, attendances related to metabolic and obesity disorders doubled, kidney failure rose by 77.7%, urinary tract infection by 74.6% and sepsis by 54.3%.

"The combination of these factors can compromise response times, care pathways and the capacity for clinical prioritisation, especially when heat episodes are prolonged or coincide with other system stressors," the report says.

The warning is particularly relevant during the holiday period, when staffing levels are reduced. Experts quoted in the source material also warned that some medicines can make it harder for patients to regulate heat, including diuretics, anxiolytics and antidepressants.

What residents can check during hot spells

Residents can follow updated heat-mortality estimates and warnings through the Instituto de Salud Carlos III tools. The institute says MoMo provides daily estimates of excess deaths attributable to heat, while the Kairós index gives five-day forecasts on the probability of heat-related mortality alerts. Both are described on the institute's official page about MoMo and Kairós.

For people looking after older relatives, neighbours or patients with chronic illnesses, the figures show where the danger is concentrated. Between 2015 and 2025, MoMo estimated 27,564 deaths attributable to high temperatures in Spain, with 2022 the worst year on record at 4,789, followed by 2025 with 3,832, according to the monitoring data cited by Euronews.

Primary sources: pmc.ncbi.nlm.nih.gov, climate-adapt.eea.europa.eu. Reported by Source Text Link, euronews.com, isciii.es, Rishav Kothari, ISCIII (Instituto de salud Carlos III), heathealth.info, thestar.com.my, ground.news, Manuel Planelles, Pablo Linde, thelocal.es, en.haberler.com, aa.com.tr, Lolita Belenguer, AGENCIAS, eldiario.es.