PureInsight | January 13, 2003
According to the Chinese traditional calendar, every year, around December 7th when the position of the sun reaches 255 degrees in celestial longitude, there will be a "Great Snow" period, one of the solar terms from that calendar. A classic Chinese book, Illustration of 72 Times in the Lunar Calendar says, "Before the month of November, wind and rain prevail, and afterwards snow prevails." It means that the weather will be much colder and the temperature will drop distinctly. The snowfall will gradually change from light to heavy. Both the frequency and the intensity of snow will be higher than those during the "Small Snow" solar period. The snow will accumulate all the time.
The earth will be covered with snow, which helps to insulate warmth for the crops and prevent droughts. As a Chinese idiom says, "a timely snow promises a good harvest." This is the meaning behind this Chinese idiom.
Translated from: http://www.zhengjian.org/zj/articles/2002/12/11/19601.html