What does "it snows and shines on the fifteenth day of the first month" mean?

On August 15, Yun Zheyue, it snows on the 15th day of the first month "is a typical meteorological proverb, which was summed up by the ancients through long-term observation of meteorology. Can spread for thousands of years, is by no means groundless. The dates in the proverb "It snows on the fifteenth day of the first month" are all lunar dates. In China, the fifteenth day of each month of the lunar calendar happens to be a full moon night.

Literally, if the moon is covered by clouds on the night of August 15, then it will snow on the 15th day of the first month, which happens to be the day when people enjoy lanterns, so the snow will fall on lanterns, forming a snowy lighting landscape. However, according to my understanding, this proverb does have some truth and reflects the echo relationship between holiday weather.

Through long-term observation of the weather, the ancients accumulated life experience and practical experience and summed up some laws between solar terms, which are called "solar terms relationship". In other words, after a certain weather appears, the corresponding weather will appear in the next few days.