Sizdahbedar or Sizdah Be-dar (also frequently stylized as "13 Bedar") (Persian: سیزدهبهدر) is the name of a ceremony in Persian Culture. Sizdah is the Persian term for thirteen. Leaving the house on the Thirteenth Day of Farvardin (the first month of Iranian calendar), and joyfully spending the day outdoors have been a national tradition since ancient times in Iran. Sizdah Bedar (in English: Getting rid of the Thirteenth) has been possibly considered as a tradition because some people believe the thirteen is an unlucky number, and everybody should get rid of the thirteen. That interpretation may be disputed since it is documented that in Persian, Bedar may also mean Raftan-e beh Dar-o Dasht (in English: Going Outdoors and Country Sides). Most of the times Sizdah Bedar coincides with the first day of April, which is known as April Fools' Day in the Western Culture.
Read more about Sizdah Be-dar: In Persian Mythology, In Zoroastrianism, On The Records, Sites of Observances, The Various Traditions of Sizdah Bedar, Sizdah Bedar in Modern Persian Poetry, Epilogue, Original Reference, See Also