More than 1,000 people may have died in Spain as a result of extreme temperatures during June, according to provisional estimates from the country’s national mortality monitoring system.
The Daily All-Cause Mortality Monitoring System, known as MoMo and operated by the Carlos III Health Institute, recorded more than 1,000 deaths associated with high temperatures during the month. Of those, 623 occurred during the week in which a severe heatwave affected much of mainland Spain and the Balearic Islands.
Spain’s state weather agency, Aemet, classified June as “extremely warm”, a term used when temperatures differ significantly from the long-term average.
Provisional figures show that the average daily temperature across mainland Spain reached 23.2°C, around 3.2°C above the average recorded between 1991 and 2020.
The scale of the difference is considered exceptional, as monthly temperature anomalies are normally measured in fractions of a degree rather than whole degrees.
June 2026 was the second-warmest June recorded since Aemet’s historical series began in 1961. The record remains with June 2025, when the average temperature reached 23.6°C, approximately 3.6°C above normal.
Experts say the latest figures reflect a wider pattern of hotter, longer and earlier summers driven by climate change.
The heatwave that affected large areas of Spain between June 22 and 24 played a major role in the rise in temperature-related deaths. Heatwaves during June were once relatively rare, but they have become increasingly common.
Aemet data show that only two June heatwaves were recorded in mainland Spain between 1975 and 2000. Between 2000 and 2025, that figure increased to ten.
Scientists say this trend is consistent with the continued warming of the planet caused by greenhouse gas emissions, particularly those generated by burning oil, gas and coal. The world’s 11 warmest years have all occurred within the most recent 11-year period.
Public health specialists warn that the true impact of extreme heat extends far beyond the small number of deaths officially classified as heatstroke.
Most heat-related deaths occur among elderly people and those with existing health conditions. High temperatures can place additional strain on the body by causing dehydration, circulatory stress and difficulties regulating internal temperature.
Researchers are also calling for greater attention to the combined effects of heat and air pollution.
Julio Díaz, a researcher at the Carlos III Health Institute who helped develop Spain’s heat-health warning system, estimates that pollution contributes to around 18% of the increase in deaths during heatwaves.
High temperatures can worsen pollutants such as ground-level ozone, which forms through chemical reactions involving heat and emissions from traffic and industry.
Experts say heat and pollution can reinforce one another, increasing the risk of cardiovascular and respiratory complications beyond the impact of either factor alone.
The Ministry for the Ecological Transition is working on plans to integrate heat and pollution risks into a broader public health strategy. The proposed measures would consider factors including fine particles, ozone, Saharan dust and smoke from wildfires.
Researchers argue that heat-health plans should include pollution-adjusted warning thresholds and could also introduce temporary traffic restrictions during periods of extreme heat and poor air quality.
Health authorities continue to stress the importance of early warnings, hydration, access to cool spaces and targeted support for vulnerable residents as Spain faces increasingly frequent and intense heat events.
