The traditional Chinese lunisolar calendar divides a year into 24 solar terms.
[1] Qiūfēn, Shūbun, Chubun, or Thu phân is the 16th solar term.
It begins when the Sun reaches the celestial longitude of 180° and ends when it reaches the longitude of 195°.
It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 180°.
In the Gregorian calendar, it usually begins around September 23 and ends around October 8.