Chubun (Kor. 추분, Chin. 秋分, lit. Autumn Equinox) is one of the twenty-four solar terms, occurring between Baengno (Kor. 백로, Chin. 白露, lit. White Dew) and Hallo (Kor. 한로, Chin. 寒露, lit. Cold Dew). Falling approximately on September twenty-third on the Gregorian calendar, Chubun usually occurs sometime during the eighth lunar month. At the equinox, day and night are equal in length, and in astronomy, the autumn equinox refers to the day when the sun passes through the ecliptic at 180°.
After Chubun, nights become gradually longer and one can feel the advance of autumn. There are no more thunder storms, humidity drops noticeably, and insects dig holes in the ground and vanish from sight. Typhoons frequently occur at this time of year. In farming communities, this is the season for harvesting crops, picking cotton, and sun-drying vegetables such as chili, sesame leaves, and sweet potato shoots. Villagers store these vegetables, along with slices of pumpkin and calabash that have been dried in late summer for consumption during the winter season. In the royal court, Chubun was the day designated for the ceremony noin seongje (Kor. 노인성제, Chin. 老人星祭), when the king prayed for the longevity of all people in the country.
A number of popular beliefs are associated with the weather on Chubun. Dry winds or rain are regarded as indicators of a good harvest while clear weather is seen as a sign of poor crop yields.