Not to cause panic in any quarters, but there are only twenty-four days until Passover! It is okay. Sit down, breathe naturally, and you will survive. It is remarkable that every year we never think that there is enough time to prepare for Passover. We worry about all of the cleaning and cooking and wonder if we will ever be ready in time, yet somehow we get it done. Yet just like Rosh Hashanah, it is either early or late. Rosh Hashanah is easier to peg, in that if it falls before September 12 it is early, but after October 1 is late. Passover is a bit harder, although most would agree that if it falls in March it is early, and if it falls after April 20, it is late. Alas, this year it is early, but next year? Next year, Passover begins on Friday evening, April 19 (my mother’s birthday again!), and that is late. Why such extremes?
Our calendar is a lunar calendar, as the ancient Israelite society was based upon agriculture and animal husbandry. The lunar month was a tangible unit, from new moon until new moon, approximately 29 ½ days, and it occurred naturally, without human interruption. The solar month is a human creation, approximately 30 ½ days. You can see that within a one-year cycle of twelve months, the lunar year concludes approximately 12 days before the solar year. Sometimes that can be as little as ten or eleven days, depending upon the number of hours. With a calendar based upon seasonal celebrations, our holidays would be earlier and earlier each year, and not naturally occur when the harvests would occur: Shemini Atzeret = fall harvest; Passover = barley harvest in the spring; Shavuot = wheat harvest. Each year our holidays would get earlier and earlier, disengaging from their origins when compared to the lengthier solar calendar. Here is where the genius of the calendar comes into play.
Within a nineteen-year cycle, the lunar calendar would be 210 days behind the solar calendar. Chanukah would fall in July, for example, and Passover in October. By dispersing seven 30-days months within the nineteen-year cycle, since 7 x 30 = 210, the calendar has been adjusted to coincide with the solar cycle. In scientific parlance, we call this “intercalation”. In Jewish calendar parlance, we call this a “leap year”. That is why next year’s Passover falls on April, as we add an additional month, Adar 2. But why do we add an additional Adar, and not some other month?
Passover is calculated based upon the lunar cycle and must fall on the night of the first full moon after the vernal equinox, which is usually March 20. With the lunar calendar constantly losing days to its solar companion, the only way to assure that Passover occurs when it is mandated in the Torah is to add the month just before Passover occurs, to let it “catch up” to the moon. If you think about it for a moment, every first Seder takes place at the full moon, inclement weather notwithstanding. That is the first full moon after the vernal equinox. As long as we don’t sing the Irving Berlin classic “I’m dreaming of a white Pesach”, and your matza balls float, all will be okay.