When does autumn begin?

Beginning of autumn is the 13 solar term in 24 solar terms, and beginning of autumn falls on August 8th or 9th every year.

"Autumn" means that summer is cool, which means the beginning of autumn. ? When you arrive in beginning of autumn, the plane tree will definitely begin to shed its leaves, which is why there is an idiom "When you lose a leaf, you will know autumn". Autumn includes six solar terms: beginning of autumn, first summer, white dew, autumnal equinox, cold dew and first frost. It is a transitional season from hot to cold, and then from cold to cold. ? On August 7th or 8th every year, beginning of autumn is considered as the time when the sun reaches 135. Twenty-four solar terms: "July Festival, set up a word to solve spring (beginning of spring).

Astronomical division method from the astronomical phenomenon, the change of four seasons is the seasonal change of the length of day and night and the height of the sun. In a year, the season with the longest day and the highest sun height is summer, the season with the shortest day and the lowest sun height is winter, and the transitional season between winter and summer is spring and autumn. Therefore, the astronomical division of the four seasons is based on the vernal equinox (March 2 1), summer solstice (June 2 1), autumn equinox (September 2 1) and winter solstice (February 2 1). Namely: spring from the vernal equinox to the summer solstice, summer from the summer solstice to autumn, autumn from the autumn equinox to the winter solstice, and winter from the winter solstice to spring.