Temperatures are expected to surpass 40C (104F) in parts of Spain, France, Greece, Croatia and Turkey.
In Italy, temperatures could reach as high as 48.8C (119.8F). A red alert warning has been issued for 10 cities, including Rome, Bologna and Florence.
The Cerberus heatwave - named by the Italian Meteorological Society after the three-headed monster that features in Dante's Inferno - is expected to bring more extreme conditions in the next few days.
It isn't just Europe that is hot. This summer has seen temperature records smashed in parts of Canada and the US as well as across a swathe of Asia including in India and China.
Sea temperatures in the Atlantic have hit record highs while Antarctic sea ice is at the lowest extent ever recorded.
And it is going to get hotter.
A weather pattern called El Niño is developing in the tropical Pacific. It tends to drive up temperatures by around 0.2C on average.
Add in the roughly 1.1C that climate change has pushed average temperatures up by worldwide and it’s perilously close to the 1.5C threshold the world has agreed to try and keep global temperatures below.
Reeta Chakrabarti presents BBC News at Ten reporting by climate editor Justin Rowlatt.