In France and the UK extreme heat warnings were issued while northern Spain recorded temperatures of 43C (109F) on Monday.
Wildfires in France, Portugal, Spain and Greece have forced thousands of people to evacuate their homes.
The UK is expected to see its hottest day ever and experts say parts of France face a "heat apocalypse".
Several parts of France saw their hottest-ever days with the western city of Nantes recording 42C, the national weather office said.