Portugal has experienced an alarming surge in excess mortality, with more than 1300 deaths recorded during a prolonged heatwave lasting twenty consecutive days. The deaths, concentrated between 27 July and 15 August 2025, have been closely linked to persistently high temperatures that strained vulnerable populations nationwide.
The figures were derived from Portugal’s official Death Certificates Information System, known as SICO, and later analyzed by the newspaper Público. Their findings revealed a 25 percent relative increase in deaths during the period compared to expected seasonal averages, highlighting the severity of this climate-driven health crisis.
Note that the reported figure represents excess mortality rather than solely deaths caused by direct heatstroke. Most fatalities were linked with preexisting conditions exacerbated by extreme heat, such as cardiovascular and respiratory diseases, combined with the effects of dehydration. These conditions endangered older adults with reduced heat tolerance.
The Institute of Health confirmed that 29 days of the 34 observation days corresponded to higher than expected deaths in the over-70 age group. The highest vulnerability was evident in individuals aged 75 and above. Their frailty and presence of chronic illnesses made them especially susceptible to dehydration and other effects of extreme heat.
No region was spared from the impacts of the heatwave. However, northern areas, central Portugal, and the rural Alentejo region were especially hard hit. Medical authorities reported that the combination of elevated temperatures, insufficient cooling, and heightened strain on regional health systems aggravated mortality rates throughout these specific areas.
Meteorological data further underlined the extraordinary intensity of the heatwave. According to the national weather service, IPMA, July 2025 ranked as the 9th hottest July since records began in 1931. Two separate hot spells occurred, with air temperature values exceeding 3 degrees Celsius above the monthly average on multiple consecutive days.
These meteorological anomalies included both daytime peaks and unusually warm nights, creating conditions where bodies could not adequately cool. Experts highlighted that such sustained thermal stress directly increases the risk of fatal complications among older adults, particularly those already struggling with cardiovascular or respiratory vulnerabilities.