Summer Begins with a 73% Increase in Heat-Related Deaths Compared to Record Year

Summer 2025 threatens to become one of the hottest and most harmful to health in recent years, with less than two weeks since the official start of the season. It has not only shattered June temperature records, as confirmed by the State Meteorological Agency (Aemet), but also marked a rise in deaths linked to excessive heat, as certified by MoMo, the daily mortality monitoring system managed by the Carlos III Health Institute.

In the first twelve official days of summer, from June 21 to July 2, 453 people in Spain died due to high temperatures. This is three times the number of deaths during the same period two summers ago and thirty times more than the heat-related deaths recorded by the MoMo system in the same period last year, when only 15 people died. The comparison with the start of summer 2024 is staggering, but it has a clear explanation: June last year was unusually wet and cool, with two and a half times more rain and half a degree below normal, minimizing deaths.

However, the truly alarming figure is that heat-related deaths at the start of summer 2025 are 73% higher than those recorded between June 21 and July 2, 2022, which was the summer with the most heat-related deaths in Spain in 22 years, with nearly 4,800 deaths throughout the season. Three years ago, during these same twelve days, 261 people died from heat, 192 fewer than this summer.

The tragic figures of 2025 are explained by the health effects of a scorching June across the country, topped with an intense and early heatwave. Last month alone, 407 Spaniards died from excessive temperatures, almost triple that of two summers ago and twelve times more than in the same month last year, when 32 people died. It is the result of the officially hottest June in the historical series, with an average temperature of 23.6 degrees, 3.5 degrees above the usual daily average for this month.

The ongoing heatwave has the worst figures of the entire period. In just five days, from Saturday, June 28 to Wednesday, July 2, experts estimate that 269 people died in Spain, averaging nearly 54 per day. This is 27 times more than the ten deaths recorded during these dates last year. The result of days when much of the country neared 40 degrees, with areas like Córdoba, Seville, Badajoz, or Jaén reaching 43, and the town of El Grado in Huelva setting a record with 46. Deaths throughout the wave clearly increased, starting with 24 on Saturday and escalating to 68, 69, and 70 on Monday, Tuesday, and Wednesday, the last days with official data.

The severe health risk posed by high temperatures is concentrated in a clear group: the elderly. MoMo estimates indicate that 97% of heat-related deaths since June 21 are among those over 65, and indeed, 66% of these deaths, two out of three, were over 85 years old. There is a higher proportion of women, 60%, which is consistent with their longer life expectancy, and the regions with a particularly high number of deaths are Catalonia, Galicia, Madrid, and the Basque Country.

The special plan against high temperatures specifies that the risk groups for heat, those who must heed health alerts and protect themselves most intensely, are, in addition to those over 65, infants and children under 4 years old, pregnant women, and people with cardiovascular, respiratory, or chronic diseases, but also those undergoing medical treatments, with mental and memory disorders, comprehension or orientation difficulties, or little autonomy in daily life.

Similarly, the Health Ministry considers those living alone, the homeless, tourists, those suffering from poverty or many hardships (with poorly acclimatized homes), and those with excessive heat exposure due to work or sports (especially between two and seven in the afternoon) as being at thermal risk.