Chinese New Year
Spring Festival, widely known as Chinese New Year in the West, is the most important traditional festival, and most important celebration for families in China. It is an official public holiday, during which most Chinese have 8 days off work.
The date of the festival is based on the Chinese lunar calendar. It falls on the first day of the first lunar month (always somewhere in the period January 21 to February 20), and ends with Lantern Festival, on the 15th day of lunar month one.
The Chinese lunar calendar usually has 354 days, so the date will be 11 or 12 days earlier each year, until it would be before January 21. At which point a 30-day month is added to the Chinese calendar year and the date is 18 or 19 days later.