Firefighters in France and Spain are racing Tuesday to suppress two of the worst wildfire outbreaks of the summer before temperatures climb back to 104 degrees Fahrenheit, a threshold officials say would make containment efforts nearly impossible.

Crews on both sides of the Pyrenees are working through a narrow weather window — lower winds, marginally cooler air — that could close within 48 hours as a returning heatwave pushes into southern Europe.

Aerial tankers and ground teams have been deployed across multiple fronts. Both governments have declared emergency status in affected regions and ordered evacuations from communities in the fire corridors.

The blazes are among the largest recorded in either country this season. Climate scientists have linked the increased frequency and intensity of southern European wildfires to rising baseline temperatures across the Mediterranean basin.

Forecasters warn the incoming heat event could push surface temperatures to 40 degrees Celsius across broad stretches of France and Spain by week's end, erasing any progress made during the current operational window.

Emergency services in both countries are expected to provide updated containment figures Wednesday morning. European Union civil protection authorities said they are monitoring the situation for potential cross-border resource requests.