Météo-France upgraded its warnings on Sunday, placing 12 departments across the south-west of France under red heatwave alert from midday Monday. The highest level of vigilance covers areas stretching from the Charente-Maritime to the Aude, while 41 neighbouring departments remain on orange alert. The second national heatwave of the summer began on 8 August with 11 departments on watch and has rapidly expanded: 28 departments were under orange alert Saturday, 42 on Sunday and 46 are expected Monday. Forecasters expect the mercury to reach 41 °C on Sunday and up to 42 °C on Monday, with the peak of the episode forecast between Monday and Tuesday. Nights are also remaining unusually warm, limiting relief for residents. Authorities have asked local prefects to prepare emergency measures and urged the public to stay hydrated, avoid outdoor exertion and check on vulnerable people. National rail operator SNCF has warned travellers of possible air-conditioning failures as rolling stock operates in extreme heat. Fire services have also raised the wildfire risk to “elevated” in 16 departments amid parched vegetation.