Ascension Weekend: France Swelters Under Record May Heat Before a Sharp Cooldown on Sunday

The 2025 Ascension weekend is shaping up to be exceptionally hot, with summer-like temperatures sweeping across the country. Météo-France is forecasting a remarkable heat spike on Friday, May 30, followed by a significant weather shift as the weekend closes.

An Unseasonal Heatwave Grips the Country

After a rainy start to the week, the Azores High has settled over France, drawing in a mass of unusually warm air. The first signs of intense heat arrived on Thursday, peaking on Friday—the hottest day of the long weekend. In the southwest, temperatures are expected to climb to 30–35°C, potentially surpassing long-standing records for the month of May.

In cities like Auch, Toulouse, Agen, and Limoges, monthly heat records may fall. Even northern regions could see highs around 30°C, including parts of Île-de-France and Alsace. At 1,500 meters above sea level, the air temperature is already reaching 15–20°C—rare levels for this time of year.

“The warm air mass moving in from Spain is exceptionally hot for the season,” says Météo-France forecaster Christelle Robert. “While we can’t definitively link this event to global warming without a formal attribution study, it clearly aligns with the ongoing climate change trend.”

Tropical Nights Signal an Alarming Trend

France also recorded its first tropical night of the year—defined by nighttime temperatures that do not fall below 20°C. Overnight from Wednesday to Thursday, temperatures remained at 21°C in Perpignan and Toulon, and 20°C in Marseille.

More such nights are expected. Forecasts indicate that cities like Paris, Toulouse, Nice, and Lyon could experience additional tropical nights. These unusually warm nights can impact public health, disrupting sleep and increasing the risk of dehydration, urinary tract infections, and kidney issues—especially among vulnerable populations.

Storms and Cooler Air on the Horizon

However, the heatwave is not expected to last. Thunderstorms may develop as early as Friday evening, especially in the Basque Country. By Saturday, stormy conditions are likely to spread to southern mountain regions, including the Pyrenees, Massif Central, and the Alps.

On Sunday, cooler air will sweep in across much of the country as a southwesterly flow intensifies. “This weather front is expected to extend from the southwest to the northeast, bringing widespread showers and significantly lower temperatures,” Météo-France reports.

Rainy, unsettled conditions are forecast to persist into Monday and Tuesday, with heavier rainfall and a more active weather system ushering in a broader cooldown—returning temperatures to seasonal norms.