When was the first frost this year? 202 1 agricultural activities of the first frost.

2. After the first first frost solar term, cold air activities became more frequent, and the temperature difference between day and night became larger. The "first frost" solar term has nothing to do with "first frost", but it doesn't mean that you will be "first frost" when you enter the first frost solar term. In fact, frost does not fall from the sky, but the water vapor on the ground condenses due to the temperature difference when it meets cold air. 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 can't be longer even for cold-resistant onions, because "the first frost can't support onions, and the longer it is, the more empty it is." In the south, it is the busy season in Sanqiu, harvesting single-season hybrid rice and late rice, planting early-crop wheat, planting early-crop rape, picking cotton, pulling cotton stalks and ploughing.