France has evacuated more than 14,000 people threatened by wildfires in the southwest, as fires also spread in Spain, Croatia and Greece.
Authorities in France's Gironde, a popular tourist region, have evacuated guards from campsites - the tourists left earlier. Fires have spread in the Teste-de-Buch and Landiras areas.
In southern Spain, more than 3200 people fled fires in the Mijas hills, though later some were able to return.
Portugal's fires are contained for now.
However, the Portuguese authorities say at least 238 people have died from the heat over the past week.
The Mijas fires in Spain are not far from Málaga, a popular tourist area. Elsewhere in Spain, wildfires have broken out in the provinces of Castilla y León and Galicia.
Ellen McCurdy, living in the Málaga area, told Reuters: "We just grabbed a few essentials and just ran really, and by that stage everybody along the street was on the move... there were a lot ambulances and fire engines."
Across the Mediterranean - from Morocco in the west to Crete in the east - thousands of firefighters and many waterbombing aircraft have been deployed. Since Tuesday, the whole region has been sweltering in severe heat, leaving vegetation bone dry.
Heatwaves have become more frequent, more intense, and last longer because of human-induced climate change. The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to carbon emissions.
The French weather service has forecast temperatures of up to 41C in the country's south on Sunday and new heat records are predicted for Monday. In Portugal, the temperature recently reached 47C.
Morocco has ordered more than 1300 people to leave their homes and deployed more firefighters to tackle forest blazes in the north. The worst-hit area is Larache province.
In Crete, Greek firefighters are battling blazes in the hills around Rethymno, on the north coast.
Some areas in south-west Turkey and on Croatia's Adriatic coast are also struggling with wildfires. A number broke out near Croatia's resort towns of Zadar and Sibenik, but they have not forced any major evacuations.
Late on Saturday, France placed 22 more regional departments - mostly along its Atlantic coast - on high orange alert.
One resident in south-west France described the forest fires as feeling "post-apocalyptic". Fires have burned 10,500 hectares of land there and Interior Minister Gerald Darmanin praised firefighters' "remarkable courage".
"Everything went so fast - the fire too, was big, big, big," Manon Jacquart, 27, told the BBC. She was evacuated from the campsite she works at early on Wednesday morning, and slept at a shelter near Teste-de-Buch where hundreds of other people also sheltered from the danger.
"I'm just worried, I'm afraid… I'm trying to be as strong as I can but I'm not ok… I want to forget this week," she said.
Meanwhile, climbers in the Alps are being urged to postpone their trips to Mont Blanc due to the risk of rock falls caused by "exceptional climatic conditions".
In Portugal, fires have destroyed 30,000 hectares of land this year, mainly in the north. That is the worst fire damage since the summer of 2017, when devastating fires killed some 100 people.
In southern Spain, holidaymakers on the beach in Torremolinos saw big plumes of smoke rising in the hills.
Planes have been a dropping fire retardant substance, as helicopters shuttle to and from the coast, collecting seawater to douse the flames.
"There are about 40 houses in our area, everyone was really nervous and standing outside or on balconies watching it," said local resident Ashley Baker.
"Even now there are fires at the top of the mountains. It moved away from here, I'm very relieved."
In Italy, the government has declared a state of emergency in the desiccated Po Valley - the country's longest river is no more than a trickle in some places.
- BBC