Solar term characteristics of first frost

The "first frost" solar term is characterized by cold weather in the morning and evening and hot weather at noon, which is the season with the largest temperature difference between day and night in a year.

Throughout the year, after entering the first first frost solar term, the cold air activities that affect our country become more and more frequent, and the temperature difference between day and night increases rapidly. Especially in Jiangnan and South China, the temperature fluctuation is more and more obvious.

However, some areas in northwest and northeast China have already presented the scene of "cold wind and fallen leaves" in early winter, so it is necessary to be alert to the strong blizzard weather brought by cold air; At the same time, the fog and haze weather in southern North China, Huanghuai and other places has also become much more.

Many areas in the south have the custom of eating persimmons. In fact, persimmons are fully mature before and after the first frost. Persimmons in this festival are deeply loved by people because of their thin skin, thick meat and delicious taste. Therefore, the custom of eating persimmons in the first frost season was formed.

Chrysanthemums are in full bloom at the first frost. At this time, in ancient times, people would hold chrysanthemum parties. To express my love and respect for chrysanthemums. Before the first frost, hundreds of famous chrysanthemums were picked, and good wine and food were placed in front of the chrysanthemum tower. First, the family bowed to the chrysanthemum god in the order of generations, and then drank wine to admire chrysanthemums, wrote poems and splashed ink. And Beijing literati mostly hold chrysanthemum parties in Tianning Temple, Taoranting, Dragon Claw Sophora and other places.

rural activity

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.

In the first frost season, most parts of the north have been harvested in autumn. Even cold-resistant onions can't grow any longer, because "the first frost can't support onions, and the longer they grow, the more empty they are." In the south, it is the peak season of "Sanqiu". Only single-season hybrid rice and late rice are harvested, and early-season wheat and early-season rape are planted. Picking cotton, pulling cotton stalks, ploughing and soil preparation.