Temperatures of 35C forecast in Bordeaux, Rhône Valley next week
France is preparing for an intense heat episode next week, with temperatures reaching 35C in Bordeaux and the Rhône Valley as a powerful high-pressure weather system establishes itself over the country. The forecast marks a significant escalation from initial predictions, which had anticipated maximum temperatures of 30C.
The anticyclone—a large high-pressure system characterized by descending air that prevents cloud formation—will move in via southern France over the weekend before rapidly covering the entire country by early next week. It is expected to remain in place for up to two weeks, bringing persistently calm, sunny weather alongside notably warm temperatures.
Updated forecasting models now indicate more intense conditions than initially anticipated, particularly across southern regions during the early phase of the weather pattern. Temperatures of 35C are possible in the Rhône Valley and around Bordeaux at the start of next week, with readings of 33C forecast along the western Mediterranean coast, across Occitanie, and in central France. Northern areas will also experience well above-average conditions, with potential highs of 30C in Brittany, Nantes, and the Paris region.
These temperatures represent a dramatic departure from typical September weather. Normal September temperatures average around 19.8C nationally, with usual highs of 20-24C depending on the region, meaning the forecast temperatures will be approximately 11-15C above seasonal norms.
Weather forecaster La Chaîne Météo projects that the national average temperature at the start of next week will reach 21.9C, just under 1C cooler than recordings at the start of this week, when several departments were under heatwave warnings.
Heatwave alerts unlikely despite high temperatures
Despite the significant daytime heat, a renewed bout of heatwave alerts remains improbable. Evening and overnight temperatures will remain relatively cool and more consistent with seasonal expectations, allowing people and buildings to cool naturally after dark. This pattern prevents the threshold conditions required for departmental heatwave alerts, which mandate that both daytime and nighttime temperatures reach specific levels for three consecutive days before orange or red alerts can be issued.
Current models suggest this intense heat will not persist long enough to trigger formal warnings. From midweek onwards, temperatures are expected to decline, remaining above average for the season but unlikely to exceed 30C except along the western Mediterranean coast.
Prolonged dry spell compounds drought emergency
The anticyclone will block rainfall across France until at least September 21. Apart from brief showers along the English Channel mid-week, the country should remain dry throughout this period.
The extended dry conditions represent troubling news for France's worsening drought crisis, which has been building throughout a summer that saw 53 heatwave days—a completely unprecedented number according to Météo-France, making it the hottest summer since records began in 1900. The country desperately needs consistent autumn rainfall to replenish historically depleted aquifers and reservoirs.
As of late August, 77 departments were experiencing the highest level of water restrictions, with 94% of aquifers showing falling water levels by mid-August. Soil moisture reached the lowest levels since records began in 1958, with satellite analysis revealing vegetation stress across approximately 70% of the country.
Several months of drought and repeated extreme heat episodes have severely dried out soils across France. By mid-August, soil moisture had reached unprecedented lows, and a prolonged dry spell in September will only compound the difficulty of restoring soil permeability. When soil becomes severely dried out, it loses its ability to absorb rainfall effectively, meaning water runs off rather than penetrating down to replenish underground aquifers.
Water restrictions in some departments have already been extended through September 30, with authorities noting that expected rainfall would not be sufficient to durably improve the situation. The continued absence of precipitation will further delay any recovery of France's stressed water systems, which also contended with wildfires that burned six times the average forest area this summer.
The forecast underscores the challenges facing France as it attempts to manage water resources through autumn, with authorities hoping for sustained rainfall to begin rehydrating the landscape and refilling depleted groundwater reserves.
