List on the 3s: Top 8 Fascinating Tidbits about the Jewish Calendar

“List on the 3s” is… well, let’s face it: I’m really not so great at actually posting one of these on a date with a 3 in it nowadays, am I?  Hell, the only reason I haven’t completely obliterated the concept of “List on the 3s” is because, as of late, it’s been one of the only things that has kept me feeling an obligation to blog. Which I enjoy doing. But sometimes I just feel like I need some kind of regularity to keep it a flowin.’

So, Shiny — what’s your excuse this time?

We’ve just completed the Jewish holiday of Rosh Hashanah, which means, literally, the beginning of the year.  According to Jewish tradition, this is Hayom Harat Olam, the birth anniversary of the world. Depending on your interpretation of the Bible as a literal Canonical source as well as the definition of the rigidity of time since the world’s creation*, we’re now in year 5769.  And in typical fashion, apparently I’m already running late.

But I thought — what better time would there be to explain a little more about the Jewish calendar?

Top 8 Fascinating Tidbits about the Jewish Calendar

8. It’s based primarily on a lunar cycle. While both the Gregorian and Jewish calendars are based on a full rotation of the Earth on its axis defining a day, the notion of what defines a “month” is different on the Jewish side. The moon revolves around the Earth on an average of 29.5 days, and Jewish months correspond to the specific cycle of that rotation. The new Jewish month corresponds with a “new moon” (often not visible from Earth). A Full moon usually occurs in the middle of the Jewish month.

7. There are 12 Months in the Jewish Calendar… For those of you keeping track at home: Tishrei, Cheshvan, Kislev, Tevet, Shvat, Adar, Nisan, Iyar, Sivan, Tamuz, Av and Elul. As mentioned above, the lunar cycle is about 29.5 days, so each month either has 29 or 30 days to it.

6 … Except when there are thirteen. The lunar calendar comes out to about 354 days in twelve months. This is fine for certain religions, such as Islam, whose calendar rotates continuously in reference to the Gregorian calendar. For instance: Five years ago Ramadan began around November, and it’s been getting progressively “earlier” as time goes by. But since many Jewish holidays are tied to agricultural seasons, there has to be a way to align the calendar months accordingly so, for instance, Passover is always a springtime holiday.

So — a system was devised to add an extra month to the Jewish calendar (Adar II: Electric Boogaloo) every leap year. A Jewish leap year takes place seven out of every nineteen years (years 3, 6, 8, 11, 14, 17 and 19). Somehow, somebody came up with this diagram which was very helpful for me once I had it explained to me for thirty-five minutes:

We’re now in year number 12 of the 19 year cycle, which means this year is not a leap year. Last year was.

Everybody got this? It only gets more complex from here…

5. I wasn’t being truthful that Adar II is the extra month in a leap year. Yes, a leap year replaces the one month of Adar with two months.  But the actual “extra month” is Adar I, and the original month which was there in the first place is Adar II. Which means that the holiday which falls during Adar during non-leap years falls during Adar II of leap years.  It’s kind of like saying that February 1 is the extra day during Gregorian leap years — and it’s followed by another 28 days of February.

Adar (and Adar II during a leap year) has 29 days; Adar I during a leap year has 30 days.

4. Biblically speaking — the technical “Jewish New Year” was actually six months ago. Which means I really have no business posting this list now. But hey — you’re probably fascinated this far into it, so I might as well continue…

You see — according to the dating per the Bible, indications were made not to the names of months (which were adopted much later from Babylonian month names) but rather the number of them. Passover, for instance, falls during the first month, which we know to be Nisan (the seventh in the order I gave above). However, tradition still holds to the world being created on what is considered the seventh month in the Bible, which we consider month #1 today.  The original Rosh Hashanah six months from now is more of a fiscal year sort of thing — it’s when the kings of Israel counted their years of rulership as well as when specific taxes were counted.

3. The Jewish New Year, Rosh Hashanah, is two days long. This goes back a bit further than the current calendar system (which was devised about 1600 years ago). At that time, the way to determine a new month was to observe a new moon.  But in order to keep everyone on one calendar,  witnesses to the new moon would approach the High Court in Jerusalem with their findings, and the court would make it official.  But there still was room for questioning as to when specifically a new moon might be — which gave a possible margin of error of one day. And by the time you had to get word to the rest of the outlying communities, a day may have already passed. So — they decided to institute a two-day Rosh Hashanah which took place 30 and 31 days after the last new moon. Because one of those days was sure to be the actual beginning of the new month which marked the new year.

If you’re already completely lost, the next part won’t help in the least…

2. The first day of Rosh Hashanah cannot fall on a Sunday, Wednesday or Friday. The reason why has to do with the holidays that follow this one: Yom Kippur is nine days later, and it’s a day when you’re supposed to abstain from eating and preparing food — and the regular prohibitions of the Sabbath apply as well. Thus — Yom Kippur can’t fall on Friday or Sunday because of technical implications regarding preparing for Yom Kippur on the Sabbath and/or preparing for the Sabbath on Yom Kippur. (You can have both the Sabbath and Yom Kippur falling on the same day.) In order to make sure that Yom Kippur doesn’t fall on a Friday or Sunday, you have to make sure Rosh Hashanah doesn’t fall on a Wednesday or Friday.

Another holiday, Hoshana Rabba, is twenty days later. Some of the customs conflict with the prohibitions of the Sabbath. In order for it not to fall on the Sabbath, you have to keep Rosh Hashanah from falling on a Sunday.

See? Simple.  So how does one keep Rosh Hashanah from falling on any of these three days of the week?

1. For the reasons above, you can delay Rosh Hashanah by 1-2 days by extending the previous year’s calendar  by 1-2 days. Technically, the formula to determine exactly when Rosh Hashanah is going to fall relies on many more complex calcluations as to which day and when during the day a new moon takes place.** (Yes, this was all derived 1600 years ago as well.)  If the new moon occurs too late during the day, it technically can be pushed off until the next day.  All you have to do is mess with the previous year’s calendar — say, for instance, the months of Kislev and Tevet. There are specific formulas built in as to when each month has 29 or 30 days based on what’s going to happen with Rosh Hashanah in the upcoming year.

Wow. This could possibly be the most boring “List on the 3s” I’ve ever done.  I really need to start coming up with some better ones. Any suggestions would be greatly appreciated.

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* See the first two chapters of Genesis. As well as hundreds of different commentaries about the feasibility of a creation narrative that takes place in six days. One of the more fascinating ones I’ve read has been Dr. Gerald Schroeder‘s The Age of the Universe. I neither support nor oppose his hypothesis.

** A great source on this can be found here: http://www.jewfaq.org/calendr2.htm