A new heat wave settles on France

March 13, 2023

Peaks of 39°C possible from Tuesday in the south of the country: a new heat wave is setting in over France, an illustration of global warming which will cause summers “increasingly hot, where 35 degrees will be the norm” .

The intensity and duration of the phenomenon are still difficult to predict, underline the experts of Météo France, but the temperatures already exceeded Monday 30 ° C on a good part of the country and are expected between 36 ° C and 38 ° C from Tuesday in the South-West and the Rhône valley, with locally possible peaks at 39 degrees.

The first heat wave orange vigilance alerts could be launched on Wednesday for certain departments, a decision which will be taken in particular in coordination with the health authorities.

The heat wave will then spread towards the Center, the East then the North, before “marking a slight and temporary drop in the north of the country on Thursday and Friday”, then again affecting the entire metropolitan territory.

It is fed by “an axis of high pressure between Morocco, France and the British Isles”, which brings up very hot air from the southern Mediterranean, explained Matthieu Chevallier, duty manager for the forecast at Météo-France, during a special press briefing.

An altitude depression on the Azores archipelago could possibly further reinforce the phenomenon, of which it is however still difficult to predict the intensity and duration, even if it could turn from Sunday into a heat wave episode, it that is to say with high temperatures day and night, which makes recovery much more difficult, especially for vulnerable people.

– 35°C, standard –

“We expect at least a duration of eight to ten days”, with a peak probably “between Saturday and next Tuesday” (July 19), indicates Sébastien Léas, from Météo France, while stressing that it is too early to evoke a phenomenon that could become comparable to the deadly heat wave of August 2003.

On the other hand, Météo France, which has been following heat waves since 1947 – the country has experienced 44 over the period – notes that they are more and more frequent under the effect of global warming. France thus experienced an episode just a few weeks ago particularly early in the season, with 40°C recorded on June 16, a record for precociousness for France.

These waves will become “more frequent, earlier and later”, notes Matthieu Sorel, climatologist at Météo France, stressing that scientific attribution studies indicate that they would be less intense in France by 1.5°C to 3° C without the effect of climate change.

“We are heading towards increasingly hot summers, where 35°C becomes the norm and 40°C begins to be regularly reached,” he said.

The last heat wave for the month of July dates back to 2019 and was exceptionally intense with average temperature records. France had thus experienced its hottest day since the start of measurements with 29.4°C on July 25 (tied with August 5, 2003), as well as its hottest night, with an average of 21.4 °C, the night of July 24 to 25.

It remains to be seen whether this new episode will see, like that of June, break records. According to the archives of Météo France, the historical maximums for the month of July range from 40.1°C in Rennes (2019) or Nancy (2019), 40.3 in Nantes (1949) or Besançon (1921), 41 .2°C in Bordeaux (2019), 41.5°C in Lille (2019), 42.1°C in Brive (2019), 42.3°C in Hyères (1982) and up to 43°C in Figari in Corsica, July 23, 2009.

The absolute record ever reached in metropolitan France is 46°C, on June 28, 2019 in Vérargues, in Hérault.