Nowruz (from Persian: نوروز‎‎, literally "[The] New Day") is the name of the Iranian peoples New Year also known as Persian or Kurdish New Year, celebrated by mostly Iranian peoples worldwide as the beginning of the new year. It has been celebrated for over 3,000 years in the Balkans, the Black Sea Basin, the Caucasus, Central Asia, and the Middle East.It marks the first day of Farvardin month and spring in Iranian calendar.

Nowruz is the day of the astronomical vernal equinox (or northward equinox), which marks the beginning of the spring in the northern hemisphere and usually occurs on March 21 or the previous/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.

Although having Persian and religious Zoroastrian origins, Nowruz has been celebrated by people from diverse ethnic communities and religious backgrounds for thousands of years. It is a secular holiday for most celebrants that is enjoyed by people of several different .faiths, but remains a holy day for Zoroastrians

https://en.wikipedia.org/wiki/Nowruz