At least 281 deaths in the two countries were linked to the heat wave.
Several towns in western Spain have been evacuated.
The head of the French firefighters federation warned about the impact that global warming is having on civil protection. “It is the firefighters, the civil security who deal with the effects on a daily basis, and these effects are not in 2030, they are now,” said Grégory Allione.
The heat waves they have become more frequent, more intense and longer lasting due to human-induced climate change. The world has already warmed by around 1.1°C since the industrial age began and temperatures will continue to rise unless governments around the world make drastic cuts in emissions.
Firefighters in Spain scrambled to protect the town of Monsagro as fires broke out further south in the Monfragüe national park, home to rare species of birds. The main N-5 road in Cáceres, just east of the park, was cut off when a forest fire reached the road.
Temperatures reached 40°C in large areas of western Spain and Portugal on Friday. In Pinhão, in the north, 47 °C were recorded on Thursday, a record for July in mainland Portugal.
However, forecasters in Spain said temperatures would start to drop on Friday.
The Carlos III Health Institute said Thursday that at least 43 people had died during the first two days of the latest heat wave, Sunday and Monday, from the heat.