Iranian Calendar or Chronology
The history of calendar in Iran dates back to 2000 years B.C. before the birth of Zoroaster. During the course of centuries the Iranian calendar has undergone much change. According to ancient sources the Iranian calendar has been derived from Babylonian calendar. In the Babylonian calendar a year consisted of 360 days (12 months; each month consisting of 30 days). Once in 6 years the year was changed to 13 months in order to adjust to the seasons). About 2500 years ago during the establishment of the Achaemenid Empire the Iranian calendar underwent other changes. Such changes were finalized in the course of three centuries. With these changes the Iranian months and days were named after Zoroastrian gods and angels. In this calendar every month had its specific name.
The Iranian official calendar is based on the rotation of the earth around the sun and the Iranian religious calendar is based on the rotation of the moon around earth. Both calendars began on the date that the Prophet Mohammad (S.) moved from Mecca to Medina (hijrat) about 14 centuries ago.
The Iranian year or Nowruz begins on the first day of spring (or March 21). Nowruz has been introduced as ‘earth’s day’ (or birthday of earth) by the United Nations. Nowruz festival lasts for 13 days.
The first six months of the solar Iranian year are made of 31 days; five months are made of 30 days and the last month of the year is made of 29 days. Lunar year is 11 days shorter than solar year. Lunar months are made of 30 or 29 days. This is why the lunar year always rotates within the solar year. For example Iranian solar year 1391 (2012) coincides with the lunar year 1434 although both calendars have started on the same day.
Click each month to see the details, Also can be downloaded on this link: Iranian Calendar (2016-2017)