Is it better for the first frost to rain or sunny?
The first frost solar term represents a season of water solar term, which is the moment when the sun moves to 2 10 degrees of the yellow meridian. The white dew condenses into frost, which means that the temperature difference between day and night is large, especially when the temperature drops below 0 degrees at night, the dew will condense into frost. There is some truth in what the ancestors said, which is the experience summed up by generations observing the weather. Because there was no weather forecast for the development of science and technology at that time, we could only observe it by experience.
The first frost sunrise is the last solar term in autumn, which reflects the change of temperature. It is the transition from autumn to winter, which means that winter is coming. The first frost solar term means that the weather is getting colder and colder, and the first frost will appear. Clear skies at night are conducive to the rapid radiation cooling of the ground or ground objects. Breeze can fully cool radiation in the thick gas layer, and can also replace the air close to the ground to ensure sufficient water vapor condensation.
Agricultural activities during the first frost
After the first frost solar terms, cold air activities become more frequent, and the temperature difference between day and night becomes larger. The "first frost" solar term has nothing to do with "first frost", which does not mean that entering the first frost solar term will lead to "first frost". In fact, "frost" does not fall from the sky, but the water vapor on the ground condenses when it meets cold air due to temperature difference changes. There is no concept of "first frost" in meteorology. Generally speaking, the first frost in autumn is called "first frost" or "first frost", and the last frost in spring is called "late frost" or "final frost".
The interval from the last frost to the first frost is a frost-free period. In the first frost season, most parts of the north have been harvested in autumn. Even cold-resistant onions can't grow any longer, because "the first frost can't support onions, and the longer they grow, the more empty they are." In the south, it is the peak season of "Sanqiu". Only single-season hybrid rice and late rice are harvested, and early-season wheat and early-season rape are planted. Picking cotton, pulling cotton stalks, ploughing and soil preparation.
Baidu Encyclopedia-First Frost