Cold Dew is the 17th solar term of the 24 solar terms. It signifies the official start of late autumn and also indicates that the weather will become colder and colder. After the Cold Dew solar term, the days gradually shorten, the nights gradually lengthen, the sunlight decreases, the hot air gradually fades, and the cold air gradually arises. The temperature difference between day and night is relatively large, and a slight chill is felt in the morning and evening.