The cities on red alert on Thursday are Bolzano, Brescia, Florence, Perugia, Rieti and Rome.

These six cities will be joined on Friday by Bari, Bologna, Frosinone, Latina, Milan, Naples, Turin, Venice, Verona and Viterbo.

The red alert indicates the highest risk level for the entire population, not just the elderly and young children.

The health ministry has warned people to avoid exposure to the sun and to refrain from outdoor activity between 11:00 am and 6:00 pm. 

Health authorities also advise people to drink liquids, eat lightly, take care to preserve medication properly, and use air conditioning correctly.

The Italian Red Cross has set up a 24-hour hotline that people can call for free for advice and assistance: 800 065 510.

In 2003, Europe’s worst heatwave in decades killed 18,000 people in Italy alone.