Tết or Vietnamese Lunar New Year, is the most important celebration in Vietnam and signifies the arrival of spring based on the Vietnamese variation of the Chinese lunisolar calendar, which usually has the date falling between the months of January or February. Tết is generally celebrated on the same day as Chinese New Year, except when the one-hour time difference between Vietnam and China results in new moon occurring on different days. According to Vietnamese Astrology, each year is associated with an animal sign, occurring in a 12-year circle.