Nowruz ( means "new day") is the name of the Iranian New Year's Day,which is celebrated worldwide by various ethno-linguistic groups and has been celebrated for over 3,000 years .Nowruz is the day of the vernal equinox, and marks the beginning of spring in the Northern Hemisphere. It marks the first day of the first month (Farvardin) of the Iranian calendar. It usually occurs on March 21 or the previous or following day, depending on where it is observed. The moment the Sun crosses the celestial equator and equalizes night and day is calculated exactly every year. Typically, before the arrival of Nowruz, family members gather around the Haft-sin table and await the exact moment of the March equinox to celebrate the New Year.