What does the light snow solar term mean?

Of the 24 solar terms, there are always a few that are easy to make wishes. For example, there is a silent light rain at the end of the rainy solar terms, and there are many snowflakes floating in the light snow and heavy snow solar terms. Will you have such an inertial association with these solar terms?

During the light snow festival, I saw this snow scene in the northeast.

Facts tell us that even in the Yellow River valley, the birthplace of the 24 solar terms, light snow and solar terms snow are rare coincidences. I have read some online articles before. It happened to rain on a rainy day. Whether it rains in the Central Plains or in the south of the Yangtze River, I am amazed at the twenty-four solar terms of my ancestors. This feeling is understandable, but the logic is a bit wrong.

In fact, the rain and light snow in solar terms and the rain and light snow in weather are two concepts.

The solar term "light snow" is a concept of climate, which is a long-term average state of atmospheric physical characteristics in a certain area and has stability. The "light snow" solar term means that the temperature in the Yellow River basin will drop below 0℃ during this period, reaching the temperature condition of snowfall. The form of precipitation in the sky can change from rain to snow, but it doesn't mean that it will definitely snow, because only temperature conditions are not enough for snowfall. Just like the "rain" solar term in spring means that the temperature in the Yellow River basin will rise above 0℃, and the precipitation form has the temperature condition of changing from snow to rain, but it does not mean that it will rain. The Yellow River Basin is dry almost every spring, and it is normal to have rain without rain. If it is cold in late spring, it will snow after the rain and solar terms.

Therefore, the light snow solar term ≠ light snow, just like the rain solar term ≠ rain, the ancients named these solar terms after rain and snow, reflecting the changing trend of temperature.

Rain and snow are weather concepts. Weather is a specific state of near-surface atmosphere in a certain area in a short time, which is complex and changeable. If it is going to snow, besides the temperature below the cloud is below 0℃, there must be enough water vapor and condensate before the water vapor can condense into snowflakes. Meteorologically, when the horizontal visual distance is equal to or greater than1000m, the depth of snow on the ground is less than 3cm, and the snowfall in 24 hours is between 0.1-2.4mm, it is called "light snow".