Mandaean calendar

The Mandaean calendar is a 365-day solar calendar used by the Mandaean people. It consists of twelve 30-day months, with five extra days at the end of Šumbulta (the 8th month). The Parwanaya (or Panja) festival takes place during those five days. There is no leap year therefore every four years all Mandaean dates (like beginnings of the months or festivals) move one day back with respect to the Gregorian calendar.