an increasingly rare phenomenon 02/02/2023

Snow is always of great interest, but its sighting in the plains is becoming increasingly rare. This is especially the case in Paris, where snowflakes have been modest in recent winters.

Rare snow in recent years

The last flakes

It would be wrong to say that there is no snow in Paris this winter. However, we cannot say that this phenomenon will leave its mark on Parisians. On the morning of December 14, 2022, it snowed lightly, but the snowflakes barely stuck to the ground (a few tracks at most on cold surfaces). On January 17, 2023, in the afternoon, flakes were also observed in the capital. Again, the snow was short-lived and did not stick firmly to the ground.

December 14, 2022, the snowiest day of this winter, a thin dusting in Paris! – photo by Dominique Hasselmann

The last snow on the ground

The winter of 2021-2022 also attracted attention with the absence of significant snowfall in Paris. For almost 2 years, the capital has not seen itself under a real white coat. The last time Parisians walk on snow-covered sidewalks is February 10, 2021. On that date, a small snow episode brought 2 centimeters to Paris. Continental cold has affected the region with a temperature of -5°C in the morning and two consecutive days without thawing. The increasingly rare winter sensations in the French capital…

2 cm of snow in Paris on the morning of February 10, 2021, the capital’s last coat of white – photo @Master_McClane

The last major episode

If we are interested in the last big snow episode that affected the capital, we have to go back about 5 years. From the afternoon of February 6th to the morning of February 7th, 2018, Paris experienced continuous snow as the blockage caused by the low pressure anomaly passed. Parisians wake up under 12 centimeters of snow February 7 morning. The episode caused record traffic especially on the N118 where many drivers had to abandon their vehicles.

12 cm of snow in Paris on the morning of February 7, 2018, the last major episode in the capital – photos by Alexandre Slowik

Global warming, urban heat island and anticyclones

Inseparable from cold snow. However, its scarcity is the main reason for the increasingly low frequency of snow in Paris. The graph below shows a clear decrease in the number of freezing days (at least 0°C) in Paris-Montsouris during the winter. Since the 1990s, most winters have recorded less than 20 days of frost, and in Paris it is no longer uncommon to experience winters with less than 10 days of frost. In addition, it emphasizes the heat island situation. Leaving Paris, the number of frosty days quickly doubles, then triples outside the suburbs.

Number of frosty days in winter in Paris-Montsouris from 1921 to 2020 – Weather chart of France

The graph below shows that Paris has seen a decrease in the number of snow days per year (at least a few flakes) since the 1990s, while the number of frosty days has also decreased. For 30 years, the first years without the smallest snowflake appeared in Paris. It is rare to see a year with more than 10 days of snow in the capital. As we saw above, the urban heat island also plays an important role. So it’s not unusual for it to rain in Paris while it snows in the suburbs.

Number of snow days per year in Paris-Montsouris from 1921 to 2020 – Weather chart of France

In general, the Paris winter of the XXI century no longer resembles the Paris winter of the last century. Average winter quarter temperature between 1931-1960 and 1991-2020 It increased by 1.7°C 4.0°C to 5.7°C in Paris! Of the four seasons, winter is the warmest season. During that period, the average number of frosty days in winter decreased from 32.3 days to 17.9 days, and days without thawing were rare (on average 2.3). Since the middle of the last century, Paris has lost half of its days with snowflake observations (from an average of 13.0 days to 7.1 days).

Evolution of climate norms for winter in Paris since 1931 – Weather cities

In addition to the evolution of temperatures, it should also be emphasized that the recurrence of anticyclonic blockages in recent years does not have a positive effect on the snowy episodes in the plain. The winter of 2021-2022, notable for the lack of snow in the French plains, was largely dominated by the Atlantic anticyclone, with extremely moderate precipitation over the country. In this context, it is not surprising that snowflakes are rare…