Firefighters battling twin fires in southwest France said Wednesday the blazes were being brought under control thanks to improved weather conditions, but had not been stopped completely.

“Our assessment is generally positive. The situation improved overnight,” local fire service spokesman Arnaud Mendousse said, saying that only 300 more hectares had burned since Tuesday evening.

French President Emmanuel Macron is due to visit the fire-hit Gironde region where a total of 20,600 hectares (206 km2) of forest have gone up in flames since last week and 37,000 people have been evacuated.

Temperatures locally have dropped from above 40 degrees Celsius (104 degrees Fahrenheit) on Tuesday to the mid-20s on Wednesday.

“We've been able to really work on our defences against the fire,” local government official Fabienne Buccio told reporters on Tuesday evening. “We managed to improve, advance and create significant fire breaks.”

“Cooler weather” had helped, she said, though the area was not expecting significant rainfall that would help extinguish the flames.

The pine forests along the Atlantic coast were bone-dry after months of drought-like conditions that have affected the entire country.

The biggest blaze is in a thinly populated area south of Bordeaux near the village of Landiras, which is being treated by police as suspected arson.

A suspect remains in custody and will be charged or released on Wednesday.

A second fire has ripped through a popular ocean-front tourist area behind the Dune du Pilat, Europe's biggest sand dune, near the Bay of Arcachon.

It is thought to have been caused by a van that caught fire last week.

Macron is expected to meet members of the emergency services, local officials and volunteers as he tours the area on Wednesday alongside Interior Minister Gerald Darmanin.