Last day of heatwave in France, arrival of violent storms and falling temperatures

The coming week promises to be a busy one, with heat , thunderstorms, heavy rain, and even hail. The heatwave, which is coming to an end this Monday, August 18, will be accompanied by significant deterioration.

On the tenth day of the heatwave , high temperatures are now concentrated around the Mediterranean. According to the latest Météo France bulletin published at 6 a.m. this Monday, seven departments in the south of the country remain on orange heatwave alert. These are the Pyrénées-Orientales, Aude, Hérault, Gard, Bouches-du-Rhône, Var, and Vaucluse. In these departments, the heat will persist: 37°C are expected in the afternoon in Montpellier, 36°C in Montélimar, and 35°C in Perpignan.

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Elsewhere, while temperatures remain summery, they are well below the extreme levels experienced by the country in recent days. Enough to breathe . The temperature is expected to reach 29 degrees this Monday afternoon in Paris, Rennes and Reims. One last night from Monday to Tuesday will still be very hot , before the high pressure system positioned over the country bows out. This will most certainly lift the heatwave alert across the entire country from "Tuesday morning" .

In Brittany , the deterioration is noticeable from this Monday morning with isolated and diffuse thunderstorms. The cause is the arrival of a cold drop : a pocket of very cold air located at an altitude of more than 5,000 meters, where temperatures are between -20 °C and -36 °C. When this phenomenon meets warmer weather on the ground, disturbances can break out, such as thunderstorms.

According to the Keraunos observatory, it is this cold drop phenomenon that will intensify the stormy weather. "Sometimes severe " events, particularly in the Pyrenees, are therefore expected, with "hail and heavy rain." "The expected rainfall accumulations could be locally significant in a short period of time. An increased vigilance cannot be ruled out, particularly in the Gard and Hérault regions," emphasizes Météo France.

In the more violent storms, hailstorms are to be feared, particularly in Midi-Pyrénées, Languedoc and in the south of the Massif Central going up towards Auvergne and Rhône-Alpes.

Tuesday will be the "most hectic" day of the week, according to La Chaîne Météo, with " occasionally strong thunderstorms " from the south of the country to Franche-Comté. Mediterranean regions are expected to be particularly exposed.

The cold snap will intensify on Wednesday. Three-quarters of France is expected to be hit by thunderstorms. Corsica and Provence-Alpes-Côte d'Azur will be threatened by hailstorms. The capital will also not escape thunderstorms. Only regions close to Belgium are expected to remain dry.

The drop in temperatures will become more pronounced, often dropping below seasonal averages. The end of the high pressure system will cause temperatures to drop drastically. In Paris, temperatures will fluctuate between 21 and 23 degrees Celsius on Wednesday and Thursday. Evenings and nights will be chilly throughout the country.

Storm activity is expected to weaken during the day on Thursday, although forecasters are still monitoring it. "The storms could bring intense rain in a short period of time. The most exposed areas are from the Pyrenees to the Rhône-Alpes, with a possible spillover into the Mediterranean regions," La Chaîne Météo experts announced. They added: " The risk of local flooding cannot be ruled out."

Calm is forecast for Friday, with sunny weather across the country. According to Météo-France forecasts, temperatures will reach 32°C in Montpellier, 22°C in Strasbourg, 21°C in Cherbourg-en-Cotentin, and 23°C in Tours.

In France, 266 weather stations recorded a temperature of 40°C or higher at least once between August 9 and 12, 2025 inclusive. This is more than in the entire second half of the 20th century.