The traditional Chinese lunisolar calendar divides a year into 24 solar terms.
[1] Dàxuě (Chinese: 大雪; pinyin: dàxuě) is the 21st solar term.
It begins when the Sun reaches the celestial longitude of 255° and ends when it reaches the longitude of 270°.
It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 255°.
In the Gregorian calendar, it usually begins around 7 December and ends around 21 December (22 December East Asia time).