What solar terms, Xiaoxue?

Beginning of winter is October Festival, and light snow is October weather.

There are twenty-four solar terms in a year, including twelve solar terms and twelve qi. In other words, there is a festival in a month, and the average interval between every two solar terms is about 30 days and 40 minutes, while the number of days in the lunar calendar is 29 and a half days. Therefore, every 34 months, there must be two months when there is no gas and no gas. A month without knots is a leap month in the lunar calendar, and a month without knots is not a leap month.