The first month of the Persian solar calendar begins on the Spring equinox. It is celebrated worldwide by various ethnolinguistic groups and falls on or around March 21 of the Gregorian calendar. 

Nowruz has Persian and Zoroastrian origins; however, it has been celebrated by diverse communities for over 3,000 years in Western Asia, Central Asia, the Caucasus, the Black Sea Basin, the Balkans, and South Asia. It is a secular holiday for most celebrants that is enjoyed by people of several different faiths but remains a holy day for Zoroastrians, and some Muslim communities.

As the vernal equinox, Nowruz marks the beginning of spring in the Northern Hemisphere The moment the Sun crosses the celestial equator and equalizes night and day are calculated exactly every year, and families gather together to observe the rituals.

While Nowruz has been celebrated since the reform of the Iranian Calendar in the 11th century CE to mark the new year, the United Nations officially recognized the "International Day of Nowruz" with the adoption of UN resolution 64/253 in 2010.