One month before Christmas, the question of a “White Christmas” comes up in discussions, like every year. However, realism supplants magic because our French climate is not conducive to snow in the plains, especially with global warming which causes a reduction in the number of days of snow in the plains as well as frost.
Statistics show decline in white Christmases in Europe
Statistical probability of snow on Christmas Eve © ERA5
Evolution of white Christmases between the period 1991-2020 and that of 1951-1980 © ERA5
Christmas Eve is on such a specific date that the chance of it snowing at that time is already low. In France, this chance has been decreasing radically since 2010, but the decreasing trend had already been established during the period 1991-2020 compared to that of 1951-1980. Between these two climatic periods, we see that the probability of having snow for Christmas Eve has especially decreased in the countries of Central Europe and in the mountains, where it was frequent. We notice a very slight increase in the north-west of France and England, where the risk was already low.
In France: no white Christmas in the plains since 2010
Number of white Christmases in France since 1950 © The Weather Channel
The last snowy Christmas Eve was in 2010. Snow was already on the ground in many areas of the northern half and was falling as a blizzard in eastern areas. This occurred in the context of the coldest December since 1969. But since then, Christmases have been generally mild, even very mild, particularly in 2022 and last year (with +4°C above seasonal averages). .
The mountain fares a little better due to the altitude, but there too, we see a clear reduction in the “white atmosphere” for Christmas Eve, where even if snow is present on the ground, it does not does not necessarily fall. Proportionally, the reduction in white Christmases in the mountains is more drastic than in the plains, because what was common in the past is more random these days.
What is the most plausible weather trend for this Christmas 2024 in France?
Statistics tell us that in France, the chance of having snow for Christmas Eve is around 1 to 5% in the plains, and 10 to 20% in the mountains and in the east. But the meteorological configuration must still be favorable (cold, conflict of air masses). Thus, it is said that the probability of having a white Christmas in France is approximately the same as that of having a “green Christmas” in Montreal (something which has also happened in recent years).
Evolution of the number of snow days in France since 1950 © The Weather Channel
A situation like that of last Thursday would have delighted snow lovers if it had occurred on the evening of December 24. In principle, this is not impossible. Because even in the context of a mild winter, a few days of snow in the plains will remain likely. But the chance of this happening is very low.
To date, seasonal weather models predict a rather mild and less rainy month of December than normal in France. This would be synonymous with fairly anticyclonic conditions. This perspective further minimizes the possibility of having snow on the plains, but also in the mountains, which would not be good news for winter sports resorts.
From a more precise point of view, the weather models predict a fairly classic alternation of disturbances and calm periods for December. To date, these models seem to indicate the passage of a disturbance around the 20th, which could bring a narrow burst of snow to our massifs before the school holidays. We will follow the evolution of this disturbance, which could then condition the weather atmosphere for the holidays.
Notre 4-week weather trendwhich will be updated this Thursday, will address the weather this Christmas period in more detail.
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