Chinese New Year: Explained
Chinese New Year starts with the New Moon on the first day of the new year and ends on the full moon 15 days later. The 15th day of the new year is called the Lantern Festival, which is celebrated at night with lantern displays and children carrying lanterns in a parade.
The Chinese calendar is based on a combination of lunar and solar movements. The lunar cycle is about 29.5 days. In order to "catch up" with the solar calendar the Chinese insert an extra month once every few years (seven years out of a 19-year cycle). This is the same as adding an extra day on leap year. This is why, according to the solar calendar, the Chinese New Year falls on a different date each year.