The Islamic Calendar begins on the Hijra: July 19, 622 CE of the Gregorian Calendar, the day the prophet Muhammed traveled from Mecca to Medina. Each year in the Islamic Calendar consists of 12 months. Odd months have 30 days while even months have 29 days. On leap years, the final month is extended to 30 days. Leap years occur during years 2, 5, 7, 10, 13, 16, 18, 21, 24, 26 and 29 of a 30-year cycle. Thus, every 30 years, there are 19 normal years with 354 days and 11 years with 355 days.