Nowruz is celebrated worldwide by various ethno-linguistic groups. Despite its Iranian and Zoroastrian origins, Nowruz has been celebrated by diverse communities. It has been celebrated for over 3,000 years in Western Asia, Central Asia, the Caucasus, the Black Sea Basin, and the Balkans.
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, and families gather together to observe the rituals.