Authorities in Sicily recorded temperatures of 48.8°C on Wednesday, as an anticyclone region of high pressure arrived over the country.
If confirmed, the blistering temperature recorded near the Sicilian city of Syracuse would be a European record, beating the existing unofficial record of 48.5 degrees, also set in Sicily, in 1999.
A spokesman for Italy's national meteorological service said the result still had to be validated.
The World Meteorological Organisation – which gives the official record as 48°C in Greece in 1977 – did not respond to requests for comment.
Elsewhere in southern Italy, the high pressure was forecast to send the mercury rising to between 39°C and 42°C before moving northwards, with weekend temperatures of up to 40°C in the central regions of Tuscany and Lazio, which includes Rome.
As the Italian capital heated up on Wednesday, tourists sought out shade and water.
"I kind of like it. It's the goal of summer to be hot and sweat and just enjoy it!" said Nora Vert, a 20-year-old from France.
The heat has raised new fears concerning fires that have blighted Sicily and the southern region of Calabria all summer.
Many have been blamed on arsonists, with the combination of high temperatures, hot winds and a tinder-dry landscape making the area vulnerable.
Firefighters said earlier Wednesday they had attended 300 incidents in the past 12 hours. A man, 77, died from burns received while trying to shelter his livestock in the countryside near Reggio Calabria.
Elsewhere in Calabria, fires threatened the Aspromonte mountain range, designated as a Unesco area of international geological significance.
The deputy head of environmental non-government organisation WWF Italy, Dante Caserta, called for more resources, such as air support, to quell the flames "or it will be too late, and we will lose forever a priceless heritage".
The Madonie mountain range, near the Sicilian capital Palermo, has also for several days been the scene of wildfires that have destroyed crops, animals, homes and industrial buildings.
Sicily's governor, Nello Musumeci, called for a state of emergency to be declared for the mountains, while national agriculture minister Stefano Patuanelli visited Wednesday to meet local mayors around Palermo.
"The fires are an emergency that need immediate responses, first and foremost with the relief that must be given to those who have lost everything," Mr Patuanelli said.
Blazes have also devastated the island of Sardinia, with 13 fires recorded during the day on Tuesday.
Over 20,000 hectares was burnt last month in the west of the island, during the worst fires seen in decades.
Southern Europe has experienced intense heatwaves and wildfires this summer as experts warn climate change increases the intensity and frequency of such extreme weather events.