When is autumn?

Entering autumn, as the name implies, is entering autumn. Traditionally, "beginning of autumn" with 24 solar terms is the starting point of autumn.

The twenty-four solar terms are determined according to the position of the sun on the ecliptic, which is different from the lunar calendar, so the twenty-four solar terms are more accurate than the solar calendar. Relative to the solar calendar, beginning of autumn Day falls between August 7th and 9th. This year (2020), August 7th is the beginning of autumn.