2022 heat wave: rising temperatures. Where and when will it be hottest?

HEAT WAVE AUGUST 2022. After a drop in temperatures and a little rain, forecasters announce a new heat wave in the middle of the week. But can we talk about a heat wave? Will it be hot everywhere in France? We answer your questions.

[Mis à jour le 23 août 2022 à 9h16] While we thought we had found seasonal temperatures, the weather forecast announces a further rise in temperatures this week in France. The summer of 2022 is one of the hottest in the history of France with already four heat waves or heat waves on the clock. But summer is not over yet, and France could experience a new heat peak, short and not very intense this last week of August. What are the forecasts? The Weather Channel announces a “hot week in France with temperatures returning well above normal, often 30 to 35°C on Wednesday and Thursday”. In addition, meteorologists specify that “the storms will return at the end of the week”.

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

• a period of high heat;
• with temperatures five degrees higher than normal for the season;
• the day and the night ;
• for three consecutive days.

When is this new heat wave expected? How long will it last? Which departments are concerned? What are forecasters predicting for the days and weeks to come? What are the steps to take to protect yourself from the heat and cool your home?

Heat wave 2022: four heat waves this summer. the forecast until mid-September

France has gone through several heat waves in less than two months with temperature records broken in many French cities. Already four in total, and a new heat wave is expected mid-week in France according to forecasters. The end of August promises to be hot, but not scorching. Here are the forecasts for The Weather Channel for the next few weeks:

• Week of August 22 to 28: a new heat peak expected. Good news for holidaymakers at the end of August, the sun should be there and the heat too, south of the Loire according to forecasters from La Chaîne Météo who predict “temperatures rising sharply, without reaching the thresholds of a heat wave”. Temperatures can reach at the hottest of the day between 30 to 35°C for the days of Wednesday and Thursday. But beware, thunderstorms are likely to arrive from the west from the middle of the week.
• Week of August 29 to September 4: heavy and stormy weather with a gradual drop in mercury.
• Week of September 5 to 11: in the south of France, good weather should be there, while in the north, it will be more mixed, with stormy showers. Please note that the reliability of these forecasts is limited, warns La Chaîne Météo.

What are the recommendations to follow during the heat wave?

Heat wave, heat peak, heat wave and heat dome: what are the differences?

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 heat wave 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.

Heat wave: what are the temperature records recorded in recent years?

If the heat wave of the summer of 2003 remains in everyone’s memory (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 thus recorded 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 more than 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 :

• Beaulieu-sur-Layon (49): 42.7°C
• Biscarrosse (40): 42.6°C
• Nantes (44): 42°C
• La Roche-sur-Yon (85): 41.5°C
• Cholet (49): 41.3°C
• Niort (79): 41°C
• Rennes (35): 40.5°C
• Caen (14): 40.1°C
• Dinard (35): 40°C
• Saint-Brieuc (22): 39.7°C
• Noirmoutier (85): 38.7°C
• Lorient (56): 37.6°C
• Brest (29): 39.3
• The island of Yeu (85): 35.9°C