"Devastating droughts and heatwaves are no longer rare. Some summers, it's not separate waves we face, but one long heatwave stretching from June through August. This is now the new normal," he said at a climate conference in Madrid.

"Before next summer, we're going to set up a nationwide network of climate shelters, using government buildings -- especially from the central administration -- and making them available to everyone," he added.

The central government will coordinate with climate shelter networks already set up by some regional governments such as Catalonia and the Basque Country, the Socialist premier said.

It will also fund shelters in neighbourhoods "that need them most, where the heat really hits people the hardest," he went on.

Barcelona, the capital of Catalonia, has led the way in setting up a network of climate shelters in libraries, schools and other public buildings with air conditioning.

Spain this year sweltered through its hottest summer ever, with an average temperature during the period of 24.2C, according to national meteorological agency AEMET.

That smashed the previous record of 24.1C set in 2022, and was the highest figure since records began in 1961.

After a warm autumn, 2025 will "probably" be Spain's third or fourth warmest year on record, AEMET spokesman Ruben del Campo told a news conference on Tuesday.

The number of heat-related deaths in Spain between May 16 and September 30 hit 3,832, an 87.6-percent increase from the same period in 2024, according to health ministry figures.

It is difficult to establish how many people are killed by rising temperatures, because heat is very rarely recorded as a cause of death.

Beyond immediate effects such as heatstroke and dehydration, heat contributes to a broad range of potentially deadly health problems, including heart attacks, strokes and respiratory conditions.