Italy is in the grip of its third heatwave of the summer, and by far the longest, with temperatures pushing 40°C in many areas.

Italian health authorities placed 14 cities, including Bologna, Florence and Rome, on red alert for intense heat again on Thursday, with all parts of the country under some level of heat warning.

Heat warnings are often heightened partly due to particularly high night-time temperatures, which have remained above 27 in some parts of the south this week.

Unfortunately for anyone hoping for some relief from the scorching condition, meteorologists say it could be a while before the country starts to cool off – and the heat is set to intensify in the meantime.

IN MAPS: How hot will it get around Italy this week?

According to Italian weather news site IlMeteo, the subtropical anticyclone dubbed ‘Charon’ that started moving in from the Sahara desert on Monday will continue to push temperatures even higher towards the end of this week.

Peaks of 42-43°C were forecast for parts of inland Sicily and Sardinia on Thursday, July 18th and Friday, July 19th, while mercury levels in many cities were predicted to reach the high 30s.

Rome temperatures were set to reach highs of 39°C on Friday, according to Italy’s national weather service, while Florence was expected to hit 37°C.

High humidity will make perceived temperatures feel several degrees hotter, particularly at night, when many cities will rarely dip below 20°C.

The only parts of the country likely to experience some respite are parts of the Alps and Apennine mountain ranges, where atmospheric instability could bring scattered summer thunderstorms.

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The heatwave is forecast until “at least the end of July”, IlMeteo meteorologist Stefano Rossi wrote on Tuesday, though the country could experience “a slight drop in temperatures” on the weekend of July 20th-21st.

Rome, Florence, Bologna, Perugia, and eight other cities were placed under red alert by Italy’s health ministry on Tuesday, and were due to be joined by Palermo from Wednesday.

This highest-level risk warning means the heat poses a threat to the general population, not just to more vulnerable groups such as young children and the elderly.

The government’s official advice is to stay indoors during the afternoon when the heat is most intense, drink plenty of water, and avoid exercise during the day.