A particularly mild start to winter: temperatures in mainland France are 10 to 12 degrees higher than the seasonal norms. According to Météo France, the last week of the year was the hottest since 1947.
This record of mildness concerns the whole of France, temperatures for eight days were five degrees above normal. This end of the year 2021 is thus placed on the first step of the podium of the mildest winters, ahead of 2002 and 2015.
Records were broken, for example in Nîmes, with 20.9 ° C recorded on December 29 (measurements made since 1922) in Marseille-Marignane with 20.7 ° C recorded on December 30 (measurements made since 1922), as well as very balmy nights like in Perpignan with 16.9 ° C on December 29 (measurements going back to 1924).
So, how to explain this spring weather? ” The mildness out of season is explained by a particular meteorological situation which has already been observed and which is not unprecedented, explains François Jobard, forecaster at Météo France. We had low and humid southwestern currents. We have also spoken of atmospheric rivers to describe a transport of humidity that has taken place from the Caribbean. “
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Mild periods accentuated by global warming
There have always been mild periods in winter, but with the global warming Today, these mild periods are taking on other proportions. This has been observed over a large part of Western Europe: in Spain (in Galicia, in La Coruna, it had never been so mild -23 ° – since 1930), but also in Belgium where there is had records of nighttime sweets.
” These gentle waves in winter are the marker of climate change, it is consistent with the scarcity of cold waves, the last in France dating back to February 2012 », Explains Christine Berne, climatologist at Météo France. And for François Jobard, this is a phenomenon that will very likely recur.
These waves of winter softness have no impact on health, unlike the heatwaves or cold waves. On the other hand, they have an impact on snow cover, avalanche risks, snowmelt with flood risks and on vegetation and agriculture, because vegetation can start its growth cycle and then be affected by gel.
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(and with AFP)