How the date of Chinese New Year is set
Chinese New Year is the first day of the first month of the Chinese lunisolar calendar. Each month starts on the day of a new moon, and the months are kept in step with the seasons by the 24 solar terms. The rule that places New Year is simple to state: the eleventh month must contain the winter solstice, and New Year is normally the second new moon after that solstice. In a year with a leap eleventh or twelfth month it becomes the third, as happened in 2033, when New Year fell on January 31.
Because a new moon can happen at any hour, the calendar fixes a reference clock. Since 1929 China has used the 120°E meridian, which is China Standard Time (UTC+8). A new moon at 23:30 in Beijing starts the month that day; the same instant is already the next calendar day further east and the previous day in the Americas. Communities worldwide still celebrate on the date set by the Chinese calendar rather than recalculating for their own time zone.
- Earliest possible date: January 21.
- Latest possible date: February 20 (1985 was the latest recent example).
- Typical gap between New Years: 354 days in a 12-month year and 384 days in a 13-month (leap) year.