The origin of the first frost

Every year around Gregorian calendar1October 23rd, when the sun reaches longitude 2 10 degrees, it is a transitional solar term from autumn to winter. There is a lot of heat dissipation on the ground in autumn, and the temperature suddenly drops below 0 degrees. The water vapor in the air directly condenses on the ground or plants to form tiny ice needles, and some become hexagonal frost flowers with white color and loose structure, so it is called the first frost.

First frost:

The first frost is the eighteenth of the twenty-four solar terms and the last solar term in autumn. Fight with your fingers; Is the longitude of the sun 2 10? ; Every year the Gregorian calendar is October 65438+2324. The first frost does not mean frost, but refers to the sudden drop of temperature and the large temperature difference between day and night. In the first frost season, it's all over. From the morning, the sun went down to the ground, Yin Qi began to condense, and the first frost weather became colder and colder. After the first frost solar term, the scene of late autumn is obvious, and the cold air goes south more and more frequently.

On the national average, the first frost is the season with the largest temperature difference between day and night in a year. The first frost solar terms are characterized by cold weather in the morning and evening, hot weather at noon, large temperature difference between day and night, and obvious autumn dryness. The first frost does not mean that the frost will fall when entering this solar term. In fact, frost didn't fall from the sky. Frost is the condensation of water vapor on the ground when it meets cold air due to the change of temperature difference. The solar terms of the first frost have nothing to do with first frost. They are not the same concept.