It is generally believed in academic circles that there have been four cold periods in China's 5,000-year meteorological history. For the period from 1 100 BC to 850 BC, that is, the first cold period in the early Western Zhou Dynasty, there are almost no relevant historical materials. The earliest records did not directly say snow, but "rain and hail", which can be found in the chronicles recorded in bamboo books. This happened in the seventh year of the Western Zhou Dynasty. "Heavy rain and hail in winter, cattle and horses die, and Hehan is frozen.