Monday, February 2, 2009

When is Chinese New Year?

A simplified version on the date of Chinese New Year is given as followed

  1. Chinese New Year must fall on a new moon. It means the beginning of things.

  2. It celebrates the beginning of spring so it must be a new moon close to solar terms Li Chun (立春). Since Li Chun (立春) fall around 4 Feb on Gregorian calendar. Chinese New Year will be the new moon near 4 Feb. Therefore, it ranges half a lunar month before and after 4 Feb. Data shows that it always fall between 21 Jan and 21 Feb.

  3. The determination of the date is based on time zone of 120 degree East (China's time zone).
There are other rules but I will not elaborate. More detail explanations can be found at here

Some further notes:
  • Chinese calendar is a lunisolar calendar (considering both Sun and Moon's movement)

  • A lunar month is around 29.53 days (therefore sometimes 30 days sometimes 29 days)

  • A lunar year consisting of 12 lunar months is around 354.37 days which is around 11 days short of Gregorian calendar. Therefore, there is a leap month around every 3 years.

  • Therefore, Chinese New Year is observed to fall around 11 days earlier each year for 2 years and then forward by 19 days on the third year. For example, this year Chinese New Year is on 26 Jan 2009. Taking 11 days away will fall out of 21 Jan 2009 range, so next year it will be around 19 days forward, that is around 14 Feb (which is in fact correct. 14 Feb 2010). So the year after next will be 11 days before, therefore around 3 Feb (which is correct again. 3 Feb 2011). In 2012, it will be 11 days before, therefore around 23 Jan (which is correct again. 23 Jan 2012). It may not always exact, allow 1 day difference as both Chinese calendar and Gregorian calendar require correction (Chinese - Leap month, Gregorian - Leap day).

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