Does the first frost belong to autumn or winter?

The first frost is the last solar term in autumn and the transition from autumn to winter. In the first frost season, everything is finished, everything goes to heaven, the sun goes to the ground, and the yin begins to condense. The cold weather began with the first frost. Yizhoushu Zhou said: "Autumn and March are empty: summer, autumn equinox, first frost."

In Lun Heng, Wang Chong of the Eastern Han Dynasty said: "Clouds and fog are also signs of rain, while summer is dew, winter is frost, temperature is rain, cold is snow, and rain and dew are frozen, all from the ground, not from the sky." Whether it is dew or frost, "it comes from the ground, not from the sky." How can it be called first frost? In fact, the name "first frost" is only used to describe the climate characteristics of "sudden drop in temperature and large temperature difference between day and night" in this season.

Agricultural activities of the first frost solar terms

After the first frost solar terms, cold air activities become more frequent, and the temperature difference between day and night becomes larger. The "first frost" solar term has nothing to do with "first frost", which does not mean that entering the first frost solar term will lead to "first frost". In fact, "frost" does not fall from the sky, but the water vapor on the ground condenses when it meets cold air due to temperature difference changes.

There is no concept of "first frost" in meteorology. Generally speaking, the first frost in autumn is called "first frost" or "first frost", and the last frost in spring is called "late frost" or "final frost". The interval from the last frost to the first frost is a frost-free period.

Refer to the above? Baidu encyclopedia-first frost