This episode linked to a localized depression between the Azores and Madeira which favors the upwelling of warm air over Western Europe, should arrive on Tuesday evening in the far south of the country, before spreading to the whole half of the country on Wednesday. south, until the weekend, according to Météo-France, which notes an uncertainty concerning the northern half.

This strong heat over several days, from mid-June, is “extremely early”, Frédéric Nathan, forecaster at Météo-France, told AFP.

The mercury has already risen very high in June in the past, in particular during one of the heat waves of 2019 with an absolute record for metropolitan France of 46°C in Vérargues (Hérault), but it was at the very end of the month.

Between Thursday and Saturday, very high temperatures of 35°C to 38°C are expected on the southern half, and the mercury could even approach 40°C locally. Minimum temperatures should not drop below 20°C at night.

A heat wave “exceptional or even close to records”, commented on Twitter the climatologist Christophe Cassou, insisting on the multiplication of this type of episodes due to global warming.

“The facts are clear; the observations confirm our projections month after month. The intensity and precocity of this heat wave is a new example,” he insisted. “Denying gravity is no longer an option. Failing to measure up is irresponsible today.”

The forecasts do not allow for the moment to qualify the episode as a “heat wave”, which meets precise criteria adapted to the geographical areas (period of intense and lasting heat, day and night, over an extended period of more than three days in general). However, it is possible that the heat wave threshold will be reached or even exceeded in certain departments, according to Météo-France.

– Danger for the most vulnerable –

In this case, since 2004 and the lessons of the heat wave of summer 2003 which killed more than 15,000 people, Météo-France can trigger orange or even red vigilance to deal with the health risks for the most vulnerable populations and socio-economic risks (transport, electricity network, etc.).

In the current state of forecasts, the extension of this week’s heat wave to the northern half of the country is still “uncertain”, but there should also be a “hot flash”, according to Frédéric Nathan, who mentions the possibility of 35°C in Paris for example Friday or Saturday.

The multiplication and intensification of heat waves in all four corners of the planet are the most obvious manifestations of global warming caused by greenhouse gas emissions, which experts and activists are calling for to reduce drastically and immediately to limit the impacts. already at work.

In France, the data clearly show this multiplication. Thus, of the 43 heat waves detected since 1947, 9 took place before 1989, the rest between 1989 and 2020: i.e. “3 times more heat waves in the last 30 years than during the 42 previous years”, underlines Météo- France.

And that’s just the beginning. Even in an optimistic scenario of a major reduction in emissions, the number of days of heat waves or heat waves should double by the end of the century in France.

This week’s episode comes after a particularly hot and dry spring which caused drought in much of France, raising fears for crops and creating conditions conducive to fires.

Despite the rains recorded last week in part of the territory, “we remain in a very worrying situation with extremely dry soils and that will not help the situation”, noted Frédéric Nathan.

In this context, more and more departments are implementing water use restrictions. As of June 12, 35 departments had issued decrees to this effect, according to the official Propluvia website, compared to 22 ten days ago.