HEAT 2023. 4 of the 50 departments placed on heat wave orange vigilance will “switch” to heat wave red vigilance at the end of the day due to very high temperatures. Peaks between 40 and 42 degrees are expected.

[Updated on August 21, 2023 at 3:14 p.m.] The fear of Météo-France is confirmed with the announcement of the passage of 4 departments in heat wave red vigilance at the end of the day by the Minister for Ecological Transition, Christophe Béchu. The Rhône (69), Drôme (26), Ardèche (07) and Haute-Loire (43) will be concerned. The Minister clarified that this decision was taken “in view of the persistence of the heat wave and the temperatures”. This will be confirmed in the 4 p.m. report from Météo-France.

Temperatures are already scorching on Monday, and the heat peak is expected for Wednesday and Thursday. This afternoon, temperatures between 35°C and 38°C are expected in the south-west with peaks of up to 40°C in Occitania. The Rhône Valley is not to be outdone since again 41°C are announced and even 42°C degrees punctually, enough to break heat records. We will have to wait until the weekend to breathe again. Météo-France indicates that “on the scale of France, this episode is the hottest of the summer of 2023, but also one of the latest with such a level of intensity”.

At the hottest of the afternoon, it will be 39°C in Toulouse, 40°C in Castres and 42°C in Alès according to meteorologist forecasts. 35°C degrees are expected in Marseille and “it will be locally 41°C in the shade, especially between Drôme, Ardèche, northern Gard and Vaucluse”, can we read in the day’s weather report.

While France is experiencing the “hottest summer 2023” heatwave episode according to Météo-France, the government has decided to activate the national telephone platform Canicule info service, the Ministry of Health announced in a press release. by France Bleu. A decision taken at the end of an interministerial crisis unit organized on August 17 at the initiative of the Prime Minister. This green number can be reached from 0800 06 66 66, and is open from 9 a.m. to 7 p.m. The Ministry of Health indicates that this number “allows you to obtain advice to protect yourself and those around you, in particular the most fragile, and to adopt the right reflexes in the event of high heat”. In addition to the activation of this platform, prevention messages are also broadcast on television and radio, says Les Echos.

As a reminder, we speak of a heat wave when these four characteristics are combined:

On June 8, 2023, the government announced the various actions implemented as part of its heat wave plan to protect the population during intense heat waves.

Heat wave and heat wave are two different things. To speak of a heat wave, the temperatures must be five degrees higher than normal for the season, day and night, and this for at least three days and three nights. The heat wave temperature threshold therefore differs according to the departments and regions. Heat waves most often occur in France in July and August. We must be vigilant from the month of June. High temperatures, even above seasonal norms, do not necessarily mean a heat wave. Most often, these are heat waves.

The term heat peak is more to be used during a sudden rise in temperature, whereas a heat wave corresponds to a longer episode. Météo France judges that a heat wave is in progress when temperatures above the monthly average are detected by more than three degrees Celsius, for at least three days.

Finally, heat dome is another term used. It settled over almost all of France in May 2022. This meteorological phenomenon is explained by a large mass of hot air from Morocco and Spain, trapped by atmospheric pressure. This usually occurs in summer, but also in spring. It results in scorching heat.

Météo France provides several levels of heatwave vigilance: level 1 (green) corresponds to a “seasonal watch”, level 2 (yellow) to a “heat warning” and it is level 3 (orange) which corresponds to “the ‘heat wave alert’. Finally, level 4 (red), the highest, determines “maximum mobilization”. In summer, it is not uncommon for several departments to be placed on orange or red alert for the heat wave.

If the heat wave of the summer of 2003 remains in all memories (and that of 1976 also among the old), France has since experienced other episodes of very hot weather. In summer 2019, several absolute temperature records were reached in different cities. According to data from Météo France, 50 cities had set a new record since July 25, 2019. While the summer of 2019 had been very hot, some records were broken during the heat wave of mid-June 2022. During the day heat wave of Saturday June 18, 2022: 150 municipalities broke a heat record, according to meteorologist Patrick Marlière, interviewed by BFM TV: “We went from 70 cities with broken monthly records, to more than 150 today in France, from the Pyrenees to the Belgian border”. The city of Nantes thus broke its record for the month of June with 39.1°C. In the South-West, records at over 40 degrees have been reached: Biarritz with 42.9°, Saint-Jean-de-Luz with 42° or Bordeaux with 40°.

The July 2022 heat wave also set temperature records on Monday July 18. Of the 63 records recorded that day, the majority are in the north, west or southwest. We can cite :