The Persian New Year is called Nowruz, and it's celebrated by Iranians of all religions on the first day of spring. The 3000-year-old tradition traces back to the Zoroastrians, and its name is a compound word in Persian composed of "now" meaning "new," and "ruz," or "day."
In 2015, Nowruz occurred on March 21. Because it always is on the same day as the vernal equinox, the date on the Gregorian calendar changes yearly. The holiday celebrates rebirth and renewal with the coming of the New Day. The Baha'i faith also recognizes New Year as the first day of spring.