The autumnal equinox is the sixteenth solar term of the twenty-four solar terms, and the fourth solar term of autumn. Douzhiyou; The sun reaches a yellow longitude of 180 °; The festival falls on September 22-24 of the Gregorian calendar each year. On the autumnal equinox, the sun shines almost directly onto the Earths equator, with days and nights of equal length around the world. The autumnal equinox, which means "half" or "half", not only refers to the equal division of day and night, but also means the equal division of autumn. After the autumnal equinox, the position of direct sunlight shifts southward, resulting in shorter days and longer nights in the northern hemisphere. The temperature difference between day and night increases, and the temperature decreases day by day
