Almost all of Italy’s largest cities will be placed under the highest — red — weather alert in the coming days due to a new wave of extreme heat, BBC News reports.

According to Italy’s Ministry of Health, a red alert had already been declared in 19 cities on Saturday, including Rome, Milan, Venice, and Naples. By Monday, the warning will be in effect in 25 of the country’s 27 largest cities.

Air temperatures in many regions have already reached +35°C, and authorities warn that the heat poses a danger not only to elderly people, children, and people with chronic illnesses, but also to completely healthy individuals.

Residents are advised to avoid being in the sun from 11:00 a.m. to 6:00 p.m., stay indoors whenever possible, and drink more fluids.

According to meteorologists, the new heatwave was caused by a subtropical anticyclone from North Africa intensifying over the Mediterranean Sea.

Against the backdrop of the extreme heat, several European countries continue to battle large-scale wildfires. In France, a major fire has flared up again in the Var department; in Greece, the evacuation of residents and tourists from fire-affected areas is ongoing; and in Spain, more than 200,000 hectares have already burned since the beginning of the year — about five times more than the average for this time of year.

According to the European Copernicus Climate Change Service, Europe remains the world’s fastest-warming continent: temperatures here are rising at about twice the global average rate, contributing to more frequent heatwaves and an increase in the number of major wildfires.