The Jewish calendar combines lunar and solar features. During Temple times, months began when the new moon was sighted in Jerusalem. An extra month was added when needed to keep the Pesach festival in the spring. Today a complex algorithm, over a thousand years old, is used to determine when months begin. As a result, the dates of the Jewish holidays in the civil calendar vary from year to year. A day on the Hebrew calendar lasts from one sundown to the next, so for purposes of religious observances a day begins at sundown of the preceding civil day. | The Jewish calendar combines lunar and solar features. During Temple times, months began when the new moon was sighted in Jerusalem. An extra month was added when needed to keep the Pesach festival in the spring. Today a complex algorithm, over a thousand years old, is used to determine when months begin. As a result, the dates of the Jewish holidays in the civil calendar vary from year to year. A day on the Hebrew calendar lasts from one sundown to the next, so for purposes of religious observances a day begins at sundown of the preceding civil day. |