What does autumn frost trail mean?

The "first frost" solar term is 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.

Meteorological changes:

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.