Urban heat island: are you familiar with this “heat bubble” phenomenon and is your city particularly exposed to it ?

Cities struggled to cool down, particularly at night. Temperatures are higher there than in rural areas. This phenomenon is called an urban heat island (ICU).

Have you ever felt a heat bubble effect in the city ? Probably, especially if you live in an urban area. After a very hot day, followed by a night where the temperature remains high, the heatwave is strong for local residents, who experience the phenomenon of urban heat islands (UHI).

A sort of dome of hot air covers the city while it can be up to ten degrees cooler in the surrounding area, Météo-France deciphers.

In the city, the stored heat is greater than in the countryside. Buildings, concrete, little vegetation and water, buildings store heat during the day and release it during the night, which slows down the cooling of the air.

Which are the 10 overheated cities?

Among the ten overheated municipalities, Paris ranks first, followed by Grenoble, Lille then Clermont-Ferrand and Lyon, lists the meteorological station. No city in Occitanie appears in this list proposed by Météo-France.

Paris (very high intensity with a maximum ICU of + 6.5 °C) Grenoble (high intensity/+ 5.5 °C) Lille (high intensity/+ 5 °C) Clermont-Ferrand (strong exposure/+ 5 °C) Lyon (high intensity/+ 4.5 °C) Reims (high intensity/+ 4.5 °C) Mulhouse (high intensity/+ 4.5 °C) Bordeaux (strong intensity/+ 4.5 ° C) Belfort (high intensity/+ 4.5 °C) Saint-Étienne (high intensity/+ 4 °C)

The urban heat island (UHI) phenomenon is strongest between 4 a.m. and 6 a.m. In a context of global warming, Météo-France underlines that "the frequency of heat waves should double in France by 2050, with greater precocity" .

One of the solutions is to reintegrate nature into the city: de-waterproof the coverings, plant trees, green the floors, facades or roofs, reports The World. Choosing light coatings for buildings or even staggering working hours or public services as well as supporting the elderly are some of the useful actions that allow us to cope with the heat.