France marked its hottest June day since World War II on Wednesdayas overheated residents across swathes of Europe coped with another day of sizzling temperatures.
A nationwide average of 26.4 degrees Celsius (79.5 Fahrenheit) made Wednesday the hottest day in France since 1945, the national weather agency said Thursday, with the thermometer hitting 37 C in some parts of the country.
Paris magistrates and lawyers were finally allowed to take off their heavy traditional robes as the French capital sweltered, while a peak in pollution linked to the heat forced regional authorities to restrict traffic in the city.
Relief was due in the form of cooling thunder storms in the western half of France on Friday, according to the weather agency.
Across the border in Switzerland, high temperatures forced the Muhlberg nuclear reactor to reduce its output to avoid heating an already hot Aar river, a spokeswoman for the BKW Energie company that runs the plant told the ATS news agency.
While the mercury was still hitting 35 C in parts of Europe, in Portugal cooler temperatures of below 30 C were helping firefighters to finally bring under control the forest fires that have ravaged the centre of the country since the weekend, killing 64 people.
But authorities warned that the risk of fire remained high in the tinder-dry Pedrogao Grande and Gois regions, and as far away as western Switzerland its weather agency reported a layer of ash from the Portuguese fires as having finally reached its skies.
In Spain, Agriculture Minister Isabel Garcia Tejerina described a "worrying" drought. The southeast in particular is in urgent need of rain, she said, with water reserves dropping to 50 percent as long as 10 days ago.
Belgium officially entered a heatwave overnight, while Italy has reported temperatures around eight degrees above the seasonal average—up to 39 C in Milan.
Explore further: Main forest fires in Portugal under control (Update)