Last week, I mentioned that some Karaites (and other Torah observant individuals) might be celebrating Passover a month after most Jews.
If you’re not familiar with this issue, I admit it can be confusing. So before you go all “Whatcha talkin’ ’bout Willis?” on me; let’s see if I can clear it up – at least a little.
The biblical year does not have a set number of months. Rather, the new Jewish year starts with the first new moon after the barley in the Land of Israel reaches a certain stage of ripeness. (See Exodus 12:2, 13:4 and 23:15.) This stage of ripeness is called “Aviv” (or “Abib”). The barley has reached the stage of Aviv when, inter alia, the barley turns from dark green (when it is rather flexible) to a lighter color (when it is brittle). Barley at the stage of Aviv is not yet fully ripe. The Karaite Korner has an informative article on the Aviv.
The “catch” is that in some years the barley is Aviv by the end of the 12th lunar month. And in other years the barley is Aviv by the end of the 13th lunar month. If the barley is not ripe at the end of the 12th month, an extra month (the thirteenth month) is added to the Jewish calendar. This extra month is referred to as a leap month.
The only way to make sure that one year is ending and the next one is beginning is to check to see whether the barley has reached the stage of Aviv. This is not controversial and the practice is even described (with some additions) in the Talmud. (Babylonian Talmud, Sanhedrin 11b.)
In the 4th Century, however, Rabbinic Judaism replaced direct observation of the Aviv with a precalculated calendar that disperses 7 leap months over each 19 year period. Karaites have historically objected to this practice and have insisted on observing the Aviv and adding leap months only when necessary. In truth, though, most Karaites of recent generations have failed to maintain this biblical precept strictly.
In recent years, there have been efforts to reinvigorate the Aviv search and you can see an update from this year’s search below.