NOWRUZ, a NEW DAY, is a celebration of the Spring Equinox. In the  Iranian Calendar it is the beginning of the year, celebrated by the cultures of ancient Mesopotamia for more than 3000 years. The moment the Sun crosses the celestial equator and equalizes night and day is calculated exactly, and the Iranian families gather around Haft Seen and observe the ritual. This year, in the Iranian calendar, this occurs on Wednesday, Esfand 30th, at 14:21:56, Iranian Standard Time. In the United States, it will occur on Wednesday, March 20th, at 02:51:56, Pacific Standard Time.