The Jewish calendar is based on the cycles of the moon and is therefore called a lunar calendar; unlike the civil calendar, which is a solar calendar and is 365.25 days long, the Jewish one is only 354 days long. In order to keep the Jewish holidays in their correct "season" (e.g. making sure that the agricultural holidays don't come in the middle of the winter) and in sync with the solar calendar, seven leap years are included in every 19-year cycle of the Hebrew calendar.
See a full Jewish Calendar for this year. Return to Virtual Jerusalem