Right Down to the Wire (San 13)

As someone who has to spend a large chunk of the summer planning for the High Holy Days, I understand that sometimes the Jewish calendar isn't always fair. Yesterday's Daf  (San 13) gave me a fascinating insight into why that is.

There are 12 months in a Jewish calendar. These months go on the lunar cycle. Subsequently a Jewish year has 11 fewer days than our calendar. If uncorrected this means that we would be celebrating our holidays earlier and earlier until we were eating Matzah in the fall and building Sukkot in the spring.

However, the Torah explicitly says that we need to celebrate Passover in the spring and Sukkot in the fall. In order to do this we add a month every once and a while called Adar Sheni to fix this. Today's Daf asked the question: when do we add this month and when do we not?

As with most things the Rabbis can't agree. Some say that if the fall equinox does not occur by the time that the intermediate days of Sukkot start then we add the month. Others say it's toward the end of Sukkot. Others say it's actually determined by whether passover falls in the spring. So to find out who wins this debate I looked at Maimonidies (turns out there's no citation for this in the Shulkan Aruch).

Here writes:  

[An extra month is added,] making the year full, because of three factors: a) the vernal [spring] equinox; b) the ripening[of the barley crop], and c) the blooming of the fruit trees.
What is implied? When the court calculates and determines that the vernal equinox will fall on the sixteenth of Nisan or later, the year is made full. The month that would have been Nisan is made the second Adar, and thus Pesach will fall in the spring. This factor [alone] is sufficient for the court to make the year full; other factors need not be considered.

Here's where it get's tricky. The vernal equinox this year falls on March 20, 2010. This year, the 16th of Nisan falls on the 31st of March. This means we're fine for this year but that next year (taking away 11 days) we'd be right down to the wire. Then we'd have to return to the big question that was posed in yesterday's Daf: is the equinox the first day of spring or the last day of winter.

Lucky for us we'll add another month before that. Moreover we have a system in place to decide the months. So I guess we're back to the drawing board about how to get Rosh Hashannah later this year. The Rabbi's said that if the infrastructure wasn't in place (roads and bridges after the winter) to allow pilgrims to offer their passover sacrifices in the Temple we could add the extra month to help them get there. Will my unfinished sermons count for an extra month?