Vietnamese people celebrate the Lunar New Year annually, which is based on a Chinese lunisolar calendar (calculating both the motions of Earth around the Sun and of the Moon around Earth). 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. It takes place from the first day of the first month of the Vietnamese calendar (around late January or early February) until at least the third day.