Nowrūz (Persian: نوروز /noʊruz/ ↔ [noʊɾuːz]; with various local pronunciations and spellings, meaning 'New Day') is the traditional Iranian new year holiday celebrated by Iranian peoples, having its roots in Ancient Iran. Since the Achaemenid era the official year has begun with the New Day when the Sun leaves the zodiac of Pisces and enters the zodiacal sign of Aries, signifying the Spring Equinox. Apart from the Iranian cultural continent (Greater Iran), the celebration has spread in many other parts of the world, including parts of Central Asia, South Asia, Northwestern China, the Crimea, and some ethnic groups in Albania, Bosnia, Kosovo and the Republic of Macedonia.
Nowruz marks the first day of spring and the beginning of the year in Iranian calendar. It is celebrated on the day of the astronomical vernal equinox, which usually occurs on March 21 or the previous/following day depending on where it is observed. As well as being a Zoroastrian holiday and having significance amongst the Zoroastrian ancestors of modern Iranians. The moment the Sun crosses the equator and equalizes night and day is calculated exactly every year and Persian families gather together to observe the rituals.