Fountains and trees create "small oases" in the city. | Miquel À. Cañellas

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While Aemet weather stations register official temperatures, in Palma there is a feeling of highs reaching 50 degrees. This is on account of the heat island effect - temperature increased by buildings, asphalt, vehicles and industry - and the thermal sensation. Enrique Morán, professor of climatology at the University of the Balearic Islands, says that at 38 degrees and with 40 per cent humidity, "you can have the feeling that it is 50 degrees". "At noon in the sun, it is getting closer and closer to the experience of being in the desert."

Palma's record temperature is 40.6C. This was at the airport in July 2020. "It was an exceptional day," explains Morán, "but in the city three more degrees were reached, to which we had to add the thermal sensation".

Joan Bauzà, associate professor of geography at the university, points out that "we must differentiate between the air temperature (measured by a thermometer in a box 1.5 metres from the ground) and the surface temperature - the one our feet feel walking barefoot on the sand, for example".

Satellite measurement and thermal sensors create "a mosaic of temperatures for different surfaces". "Some surfaces absorb a lot of solar radiation, such as dark and impermeable ones like asphalt. Porous surfaces with light colours, such as sandstone, or natural surfaces with vegetation have more moderate temperatures."

"Hence the importance of trees in cities - they generate shade and can have a temperature up to 10 degrees lower than an artificial surface such as asphalt. The leaves have the capacity to retain the particles generated by vehicles. A balanced mosaic with an abundance of natural surfaces, layers of water and more porous materials is important."

In Palma, the sea breeze does help to cool the city, but only so much. The town hall's plan to plant 10,000 new trees will help to reduce the heat sensation in the city, but it is important that these are spread throughout the city. Together with fountains, says Bauzà, these should create "small oases" for the city.