Regional authorities in Sicily recorded temperatures of 48.8 degrees Celsius on Wednesday, which if confirmed would be a new Italian and European record.
A spokesman for Italy's national meteorological service said the result still had to be validated.
Sicily's governor, Nello Musumeci, called for a state of emergency to be declared for the mountainous regions which have been battling fires.
Southern Europe has experienced intense heatwaves and fires this summer and experts warn climate change increases the intensity and frequency of such extreme weather events.