What does cold dew mean?

Cold dew, the seventeenth of the twenty-four solar terms, belongs to the fifth solar term in autumn, which indicates the official end of the autumn season. Finger e; Longitude of solar arrival195; Celebrate every year from July 7th to 9th in Gregorian calendar 10 year 10.

According to the climatic characteristics, in the cold dew season, autumn has entered the vast area in the north, late autumn in the northeast and winter in some areas in the northwest. Autumn is getting stronger in the south.

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Phenological characteristics

Cold dew is a solar term reflecting the characteristics of climate change. Cold dew, white dew and first frost all indicate the phenomenon of water vapor condensation, and cold dew is a transition from cold to cold. Compared with the white dew, the temperature drops a lot, and the dew on the ground is colder, which is likely to become frozen dew, so it is called cold dew.

In ancient times, solar terms were divided by "bucket handle pointing method". When the bucket handle of the Big Dipper pointed in the E direction (that is, the northwest direction), it was a cold dew solar term. From the Han Dynasty to the end of the Ming Dynasty, solar terms were divided by the method of "balancing qi". At noon that day, the sun shadow was measured with a standard watch. The length of the sun shadow was eight feet two inches, which is equivalent to 2.0438+08 meters today.

Since 1645, solar terms have been divided by the method of "fixing qi", and when the sun reaches longitude 195 degrees, it is cold dew. Generally speaking, the solar term of cold dew falls on the 8th or 9th of 10/0 of the Gregorian calendar every year.

Yuan Wucheng's "Twenty-four Solar Terms" said: "If it is cold in September, it will be condensed." Cold dew means that the temperature is lower than that of the white dew, and the dew on the ground is colder and will soon condense into frost.

In the cold dew season, Nanling and the vast area to the north have entered autumn, and the northeast and northwest regions have entered or are about to enter winter. In the capital Beijing, you can see the first frost in many years. In addition to the perennial snow on the Qinghai-Tibet Plateau, it has generally begun to snow in the northeast and northern Xinjiang.

Baidu encyclopedia-cold dew