Is There a Leap Day on the Jewish Calendar?

Answered by
Rabbi Emily Langowitz

Is there a Leap Day on the Jewish calendar? No, but there is a leap month!

On the secular Gregorian calendar, we add a leap day in February every four years to account for the extra quarter day in the earth's rotation around the sun. This ensures that our usual 365-day calendar continues to align with the seasons.

Unlike the secular calendar, which is based on the connection between the earth and the sun, the Jewish calendar is based primarily on the connection between the earth and the moon. Each of the Hebrew months begins and ends with the new moon, so Hebrew months are shorter than the months on the secular calendar and the Hebrew calendar has far fewer than 365 days.

Because many Jewish holidays are tied to certain seasons, a leap month is added seven times within a nineteen-year cycle (years 3, 6, 8, 11, 14, 17, and 19) so that the years stay long enough to keep the spring holidays in the spring and the fall holidays in the fall. This is why, though there is some variance, Jewish holidays never stray too far from the seasons. This system is called a lunisolar calendar, a lunar calendar that is also influenced by the earth's orbit around the sun.

The leap month is added in the spring, immediately following the Jewish month of Adar. The extra month is called Adar II, or Adar Bet. During Adar, we celebrate Purim, and the month is seen as one of happiness and celebration. In a Jewish leap year, not only do we benefit from keeping all the holidays in their respective seasons, but we also have the chance to enjoy an extra month of joy!