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When is the autumn wind? What month?

Autumn solar terms, namely the autumnal equinox solar terms, are also important solar terms in agricultural production. After the autumn wind, the position of direct sunlight shifted to the southern hemisphere, and the northern hemisphere got less and less solar radiation, while the ground lost more heat, and the temperature dropped significantly faster.

The autumnal equinox is the sixteenth solar term in the twenty-four solar terms of the lunar calendar, usually on September 22nd or 23rd every year. The climate in the south began to decline from this solar term. First, on this day, the sun reaches the longitude of the Yellow River 180 degrees and directly hits the equator of the earth, so a day is 24 hours, each 12 hours; There is no extreme day and night phenomenon in the world. After the autumnal equinox, the polar night range near the North Pole gradually increases, and the polar day range near the South Pole gradually increases.

Agricultural proverbs say, "An autumn rain leads to a cold", "Autumn rain leads to a cold night", and "In August, geese bloom and first frost is the first step".

Extended data

The current 24 solar terms adopt the method of "constant gas". According to the position change of the earth on the ecliptic (the earth's orbit around the sun), each node corresponds to a certain position that the earth reaches every time it runs 15 on the ecliptic. It is a knowledge system formed by observing the movement of the sun in a year and understanding the changing laws of the four seasons, climate and phenology in a year.

It divides the sun's annual trajectory into 24 equal parts, each 15 is an equal part, and each equal part is a solar term, starting in beginning of spring and ending in severe cold. Each solar term represents different changes in climate, phenology and time. China's lunar calendar is a combination of yin and yang, which is based on the movement of the sun and the moon, so adding 24 solar terms can better reflect the cycle of the sun's movement.

Baidu encyclopedia-autumn wind

Baidu encyclopedia-autumnal equinox