In a few days, France went from a heat episode to much milder temperatures. Nevertheless, it is incorrect to speak of a “cold wave” to describe the situation in mid-September 2022.
Barely a few days after the final heat peak of summer 2022, much milder temperatures are settling in France as autumn approaches. The expression “cold wave” was used, from September 15, 2022, to qualify an episode which would last the weekend of September 17 and 18, and again all of the following week. It recalls the expression “heat wave”, often used during the summer of 2022, the hottest ever recorded on the European continent.
However, Meteo France has warned : it is not a “cold wave”, nor a “polar cold”. This is ” simply a drop in temperatures over the country. They will be lower than normal, especially the minimum temperatures […] after many days well above normal since the beginning of the year “. Monday, September 19 in the morning, Météo France has reported minimum temperatures of 3 to 6°C below normal in France, such as 2.4°C in Clermont-Ferrand or 4.3°C in Alençon.
It is true that ” it’s been 45 years since it’s been this cold this early in the fall », confirmed Gaétan Heymes, forecasting engineer and snow expert for Météo France. Nevertheless, he adds“ the impression of cold comes more from the sudden drop in temperatures from record lowsthan the absolute value of the temperatures observed on the 18th, which is, once again, not unprecedented for the period “. Never had we observed, since the beginning of the measurements in 1947, ” such a sharp drop in the minimums in five days or less in September: -11.8°C “.
When can we speak of a “cold snap”?
What are the criteria for being able to speak of a cold snap? It has to be ” a lasting and extended episode of cold (at least 3 days) “, according to Meteo France. Nationally, we speak of a cold snap when ” national average temperature [descend] at least one day below a certain threshold (-2°C) “. It is also possible to speak of a cold wave on a regional scale: for this, the episode must last at least 2 days and the temperatures must be significantly lower than normal for the season in the region.
In France, cold peaks usually occur in winter, in January or February. Nevertheless, ” early episodes (in November or December) or late episodes (in March) are also possible “, recalls Météo France. Like heat waves, episodes of intense cold can be a danger to our body.