The heat wave baking Europe and threatening to make this the hottest summer ever will be dialing up temperatures even more in coming days, thanks to another system from the Sahara.

Countries in the southern parts of the continent, already enduring forest fires and heavy thunderstorms, are expected to see their thermometers soar past 40C (104F). Italy’s health ministry issued emergency alerts for 16 cities — including Rome, Florence and Palermo — on Sunday, recommending that people avoid direct sunlight in the hottest hours.

Temperatures are set to rise again nationwide through Wednesday, with a potential peak of 46C in Sardinia and a record-breaking 42C in the capital, according to forecaster Meteo.it. Forecasters expect the heat wave, dubbed Charon after the Greek deity that ferried souls to Hades, to relent from Thursday onward.

Italy was among the hardest hit by last year’s warm weather, reporting about 18,000 heat-related deaths, more than any other European nation.

Spain also keeps broiling. Madrid temperatures will rise to 41C, according to national forecasting agency Aemet. An “extreme risk” alert has been issued for the Andalusia region in the south.

On La Palma in Spain’s Canary Islands off the coast of Africa, a wildfire that started Saturday abated with the help of better weather conditions, Associated Press reported, citing the authorities. The blaze forced the evacuation of more than 4,000 residents.

Israel joined Europe in suffering from scorching weather over the weekend. Israeli Prime Minister Benjamin Netanyahu was discharged from the hospital on Sunday after being treated for dehydration following a day in the sun.

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Climate change is increasing the frequency of extreme weather across the Northern Hemisphere, underlining the increasing urgency to cut greenhouse gas emissions, according to the World Meteorological Organization. Last month was the hottest June on record.

Europe had the warmest summer on record last year, contributing to an estimated 60,000-plus deaths across 35 countries, marine heat waves and extreme weather.

It’s a different story in northern parts of the continent, where the weather is far milder. London temperatures are forecast to peak at 23C on Tuesday, according to the Met Office.