Data News Are you waiting for the snow？ The data look at the snowfall in Beijing.

Expert Consultant: Zhang Zhifu, Senior Engineer of National Meteorological Information Center.

All night long, the city was covered with silver and snow-this is the winter picture that many people are looking forward to. According to the forecast of Beijing Meteorological Observatory,twelvemoon10Japan, Beijing will usher in2023The first large-scale obvious snowfall in the winter of 2008.

Are there fewer and fewer days of snow in Beijing?

In recent years, the biggest feeling of people living in Beijing is that there seems to be less and less snowfall. When I was a child, I could make a snowman and have a snowball fight in winter. Now it is hard to meet snowflakes. Let’s follow the meteorological data to see if there are really fewer snowy days in Beijing.

From the data of winter snowfall days in Beijing (Observatory Station) from 1961 to 2022, it can be seen that the year with the most snowfall observed in winter in Beijing was the winter of 1963, with a total of 29 days, and the second largest was the 27 days in 1968. The year with the least snowfall days appeared in the winter of 1982, with only three days, followed by the winters of 2006, 2010, 2013 and 2022, with only four days of snowfall in the whole winter.

In addition, since 2000, the annual average number of snowfall days in Beijing has decreased compared with that in the 20th century. Among the top 10 snowfall days in history, the years after 2000 accounted for 7 seats. Since 2000, there have been only three years in which the number of snowfall days has reached more than 20 days, namely, the winter of 2000 (22 days), the winter of 2002 (23 days) and the winter of 2012 (23 days).

At present, during the heavy snow solar term, as the temperature gradually drops, compared with the light snow solar term, the probability of snowfall in the heavy snow solar term is higher. According to the historical data of "Tianqing" of the National Meteorological Information Center, during the heavy snow solar term from 1991 to 2020, the average snowfall days in Beijing were 0.8 days, and the average precipitation was 0.92 mm.

How is the first snow day defined in Beijing?

According to the definition of the first snow day in Beijing (Trial), the first snow day in Beijing refers to the date when a large-scale snowfall occurred for the first time in Beijing. There are 20 national meteorological stations in Beijing, and there are five observation stations in the urban area, namely Observatory, Chaoyang, Haidian, Fengtai and Shijingshan.

Meet one of the following conditions can be identified as the first snow day in Beijing that year:

First, snowfall was observed at more than 10 stations in 20 manned weather stations in the city;

Second, snowfall has been observed at five observation stations in the urban area (Observatory, Chaoyang, Haidian, Fengtai and Shijingshan), or at three or more of the five stations in the urban area, and the snowfall of at least one station is ≥ 0.1mm..

When does the first snow usually come in Beijing?

According to statistics, the first snow in winter in Beijing mostly occurs in November and December. The average first snow day in Beijing from 1991 to 2020 is December 3rd.

The statistical period of the first snow day is from October 1st of that year to May 31st of the following year. In some years, the first snow only appears in January or February of the following year, so there will be new year’s eve. For example, the sunrise of the first snow in winter in 1970/1971 is now on January 19, 1971 (the years with the first snow in January and February are the following year of the statistical year).

According to statistics, since 1961, the earliest date of the first snowfall was October 31st of the winter of 1987/1988, which was the only snowfall in Beijing since 1961, one month earlier than the average first snowfall date.

The latest appearance date was February 11th of the following winter in 1983/1984, which was more than two months later than the average first snow date. It is worth mentioning that the first snow day ranks in the top five at the latest. Except for the winter of 1983/1984, the second to fifth snow days all appeared after 2010.

(Author: Su Jessie
Editor in charge: Yan Hong)