After a brief respite expected over the weekend, temperatures are set to rise sharply again across much of France. A particularly hot air mass will move up from Spain and North Africa starting Tuesday, July 28, with a period likely to reach heatwave thresholds as early as Wednesday, July 29.
The mercury will jump in just 48 hours
The change should be rapid. Temperatures could rise between 5 and 10°C in two days due to a south to southwesterly flow. A low-pressure system positioned over the Atlantic would encourage the northward movement of hot air, while high pressure would persist over Western Europe.
At an altitude of approximately 1,500 meters, the air mass could reach 24 to 26°C, exceptionally high values for France. On the ground, the heat would initially spread from the Southwest and West before reaching the central regions, the East, and part of the North.
Up to 38 or 40°C from the Southwest to the Centre
Between Wednesday, July 29th and Friday, July 31st, temperatures could exceed 35°C from the Southwest to the central regions. Peaks of between 38 and 40°C are expected in the most exposed areas, particularly between the Aquitaine Basin, the Toulouse region, and the Centre.
The 30°C mark could also be reached in the north of the country. Temperatures could be more than 10°C above normal in some areas between the Southwest and Northeast. Nights will also become much warmer, with minimum temperatures likely to remain above 20°C in several cities.
Three-quarters of the country could be affected
The most intense heat is expected to cover a large part of the country. The Southwest, the Centre, the Rhône Valley, Burgundy, the Grand Est and some areas of the Paris Basin appear to be among the most exposed areas.
The Channel coast could maintain more bearable temperatures thanks to the maritime influence. The Mediterranean coast could also remain slightly cooler when sea breezes persist, though it will still experience intense heat.
The most extreme forecasts predict temperatures exceeding 40°C in some areas, but these values remain highly uncertain. The European model currently shows lower temperatures than some American scenarios, with differences exceeding 8 to 10°C for the same city and the same day.
The heat is likely to last until the beginning of August.
The main uncertainty concerns the duration of the heatwave. Stormy weather could gradually push the hot air back starting over the weekend of August 1st and 2nd. Another scenario, however, predicts the persistence of high pressure, which would trap the hot air mass over France.
The forecasts for the week of August 3-9 maintain a very hot signal across much of the country. A renewed surge could prolong the heatwave or trigger a second peak after a brief lull in thunderstorms. Some projections show no clear break before August 6, but this date is still too far off to be stated with certainty.
A fourth warning after an exceptional start to the summer
France has already experienced several exceptional heat waves since the end of spring. From May 21 to 30, an early and prolonged heatwave broke numerous monthly records. A historic heatwave then struck the country from June 17 to 30, with the national 24-hour average temperature reaching 30°C for the first time on June 24 and 25.
A third heatwave began at the start of July. Record temperatures were recorded, with 42,1°C in Saintes, 41,2°C in Narbonne, 40,9°C in Perpignan, and 40,5°C in Royan. Nights were also stifling, with lows of 27°C recorded in Nîmes and 25,9°C in Le Mans.
Extreme drought and heightened fire danger
This new rise in temperatures would occur on soils that are already extremely dry. By July 22, their moisture content had reached an unprecedented level so early in the summer, lower than that observed on the same dates in 1976, 2022 and 2025.
The return of intense heat would further accelerate the drying out of vegetation. The fire risk could become very high again, even extreme in windy areas, particularly in the Southwest, the Mediterranean coast, and the Rhône Valley.
The heatwave classification still needs to be confirmed.
The scenario of a fourth heatwave is strengthening, but its final classification will depend on the temperatures actually observed during the day and night, the duration of the episode and the thresholds specific to each department.
A brief spike to 38 or 40°C can still constitute a heatwave if it is followed by a rapid drop in temperature. However, several consecutive days and nights above health thresholds would confirm a new heatwave. Forecasts for the coming days will help determine its extent, intensity, and true duration.
