Sizdah Be-dar
April 1, Monday
Sizdah Bedar also known as Nature's Day is an Iranian festival held annually on the thirteenth day of Farvardin (same as Aries), the first month of the Iranian calendar, during which people spend time picnicking outdoors. It marks the end of the Nowruz holidays in Iran.
Generally, among Iranian festivals, "Sizdah Bedar" is a bit vague in terms of historical roots. There is no direct mention of such a celebration in history books prior to Qajar era. But in ancient sources, such as Shahnameh, there is a reference to "the thirteenth day of Farvardin". The popular belief is that ancient Iranians celebrated the 13th day of Nowruz after twelve days of celebrating, each day represents a month of the year. It was an official ending to Nowruz and a beginning to the remaining twelve months of the year.