The Jewish calendar is a lunar calendar; comprising of five 29-day months and seven 30-day months, totaling 354 days a year, with the new day beginning at sundown, based on the creation account, “Evening and morning…” (Gen 1:5). To balance the difference between the moon year and the Gregorian or sun year of 365¼ days, a ‘leap month’ is added when necessary. The Jewish festival dates are fixed days on the Jewish calendar that follow the cycle of the moon, although they vary on the western or Gregorian calendar. Many Biblical scholars relate significant end-time events to the Jewish calendar and their feast days.
See also: church calendar.