Extreme heat: Météo-France does not rule out a heatwave as early as this week

France is bracing for another heatwave, which could turn into a full-blown heatwave by midweek, according to Météo-France. Temperatures are expected to exceed those recorded during the exceptional heatwave at the end of May, with highs potentially reaching 38°C in some areas on Thursday.

According to forecaster Corentin Perrot, interviewed by AFP, "we know that we're entering a heat wave, possibly even a full-blown heatwave, starting in the middle of the week." This rise in temperatures will affect a large part of the country and is expected to be particularly pronounced due to its proximity to the summer solstice.

Temperatures well above normal

Starting Wednesday, temperatures will rise sharply. Thursday could be the peak of this episode, with highs reaching:

• 38°C in Nevers;
• 37°C in Paris;
• 37°C in Brive;
• 36°C in Lyon;
• 35°C in Toulouse.

Minimum temperatures will also remain very high, often between 18°C ​​and 22°C in several regions. These warm nights will limit nighttime cooling and accentuate the feeling of heat.

A possible heat wave

Météo-France distinguishes a simple heat episode from a heat wave thanks to the National Thermal Indicator (ITN), calculated from temperatures recorded in 30 metropolitan meteorological stations.

For a heat wave to be officially classified, two conditions must be met:

• an ITN greater than 23,4°C for at least three consecutive days;
• an ITN reaching at least 25,3°C on one of these days.

At the end of May, the ITN had reached 24,8°C, a record for a month of May, although it did not meet all the criteria for a heat wave.

Longer days, warmer nights

The unique aspect of this event lies in its timing. A few days before the summer solstice, the days are among the longest of the year.

“The nights are short, which limits the nighttime drop in temperatures,” Corentin Perrot points out. This situation promotes heat accumulation and makes these episodes more difficult for vulnerable populations.

Thunderstorms expected at the end of the week

The exact duration of this episode remains uncertain. Its evolution will depend on the arrival of thunderstorms expected from the end of the week.

These disturbances could bring gradual cooling but also locally cause violent phenomena, such as heavy rain, gusts of wind or hail.

A phenomenon linked to global warming

Climate scientists point out that the increasing frequency of extreme heat events is one of the most visible manifestations of global warming.

According to the scientific consensus, heat waves are becoming:

• more frequent;
• longer;
• more intense;
• earlier in the season.

Summer 2026 could therefore be part of a trend observed for several years, with temperatures regularly above seasonal norms.