Heat wave 2023: a scorching start to September, up to 39 degrees


Heat wave 2023: a scorching start to September, up to 39 degrees

HEAT WIND 2023. The month of September begins with strong heat in the west and part of central France, where 30 degrees will be reached and even exceeded at the start of the week. What is the forecast near you?

[Updated September 4, 2023 at 9:43 a.m.] Children are heading back to school in the sun and heat for the start of the 2023 school year. A heat wave seems to be setting in over France this week and Météo-France places 21 departments in the western half of the country on heatwave yellow vigilance this Monday, September 4, 2023. Forecasters are announcing very high temperatures in the south-west of France with 37 degrees expected in Angoulême this afternoon, 36 degrees in Limoges , and even 30 degrees in Brest. Peaks at 39 degrees locally are expected. The mercury should remain high all week and Météo-France warns that "heat wave vigilance may be gradually extended to other departments".

Météo-France has placed 21 departments on heatwave yellow vigilance this Monday, September 4, 2023





Charente Maritime

Two Sevres





Indre et Loire



loire Atlantique




Puy de Dome




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

On June 8, 2023, the government announced the various actions implemented as part of its heatwave plan in order to protect the population during extreme 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, while 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 level 3 (orange) corresponds to “the 'heatwave 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 heatwave.

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 towns 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 :

During the heat wave of August 2023, many records were also recorded. Among them :