What are the characteristics of the first frost solar terms?

The first frost solar terms are characterized by cold weather in the morning and evening, hot weather at noon, large temperature difference between day and night, and obvious autumn dryness. On the national average, the first frost is the season with the largest temperature difference between day and night in a year. After entering the first first frost solar term, the cold air activities affecting our country became more and more frequent, and the temperature difference between day and night increased rapidly. Especially in Jiangnan and South China, the temperature fluctuation is more and more obvious; Some areas in northwest and northeast China have shown the scene of "cold wind and fallen leaves" in early winter.

During the first frost period, it usually lasts from late June 10 to1early October 10. As dry and cold air gradually dominate the whole country, warm and humid air is marginalized, and many weather with characteristics of summer and early autumn exits, so the weather is relatively simple. Before and after beginning of winter, there were often strong winds and cool weather, and some places entered winter in a short time.

The ancients in China divided the first frost into three stages: the first stage was the sacrifice of animals by jackals; Second, the vegetation is yellow; Three stings are salty. At this time, jackals and other animals began to catch prey for the winter; The leaves are all yellow and falling; Hibernating animals also hide in caves and go into hibernation without food.

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.