Have you noticed that Pesach is never on time? You always hear people say that “Pesach is early this year”, or in our case, that “Pesach is late” (it starts Friday 22 April this year).
Actually, it is always on time, that time being 15 Nissan. So why is it early or late? Well, you see, the Jewish calendar is based on two physical phenomena — the Earth turning around the Sun (365 1⁄4 days) and the moon rotating around the Earth (291⁄2 days). When the Torah tells us about the dates of festivals, it describes the cycles of the moon, and the festivals fit into 12 lunar months each year. Problem! That Lunar year is around 11 days shorter than the Solar year.
If you have Muslim friends, you will know that Ramadan is at a different time each year, and that is because they have a purely lunar calendar and so each year Ramadan is 11 days earlier. If we did the same, then Rosh Hashanah would not always fall out in Israel’s Autumn and Pesach would not be in Spring, and that just would not work. So, we had to “intercalate” between the Lunar and the Solar calendar, and that means that every 19 years there are 7 leap years (literally in Hebrew called ‘pregnant years’) where we add an extra Adar. In fact, as I write this we are in a pregnant year, and it’s the end of Adar Aleph, about to begin Adar Beit. That’s why Pesach is ‘late’.
Now, to the next question — how long is Pesach? Well, if you have a South African calendar hanging on your wall, chances are that it marks eight days for Pesach. If it’s an Israeli one, there will be seven! Which one is right? Well, if you read the Torah, you will see that Pesach has seven days, but the problem was getting the date right back before we had more sophisticated tools for calculating time. A month began when the new moon was sighted, and so witnesses had to first see the new moon, run to the beit din and testify that they had seen it, and only then, after careful checking, would the new month be announced. If that month happened to be Nissan, you then had two weeks to let everyone know that the month had begun and Pesach would fall on the 15th. All fine if you lived in Jerusalem, or even the towns nearby, but if you lived in Greece or Babylon, there was no guarantee that the messengers would make it in time to be sure that you had the right day.
Going back to our calendar discussion above, since a lunar month is about 29 1⁄2 days, a Hebrew month (which has to have a whole number of days) can have either 29 or 30 days and depending which would affect the date of your festival. What the outlying communities started to do was to observe Yom Tov on both possible days to be sure that they had it right at least on one of them — and so began the diaspora tradition of two days yom tov. In the case of Pesach, there is a yom tov on the first and seventh day, and so Pesach became an eight-day festival (two days for the seventh day) outside of Israel.
Around 1600 years ago, the great rabbis of the time working under Hillel II, established a fixed calendar based on mathematical and astronomical calculations which we still use today. So, if we know without doubt which is the right day to celebrate yom tov whether you are in Israel or outside, why isn’t everyone on the same calendar by now? The Talmud discusses whether or not to continue the system of two days yom tov in the diaspora, and advises that minhag avoteinu (customs of the ancestors) should be maintained. When Progressive Judaism started up in the 1800’s in Germany, one of the decisions was to return to observance of the Torah calendar for festivals, as there was no longer a chance of getting it wrong.
And that is why in the Jewish world today, you have everyone in Israel (Progressive and not) keeping seven days Pesach, Progressive Jews outside of Israel keeping seven and Orthodox Jews outside of Israel keeping eight days. In practicality that means that everyone starts together on 23 April (seder night is the 22nd) but while for Orthodox communities outside of Israel the Saturday 30 April is 8th day Yom tov, for the rest it is Shabbat.
Confusing? Well, Judaism never claimed to be simple, but at least the logic that underpins it all is clear. And I hope that you can see now that Pesach is actually never early or late, but right on time. Whether you are a seven-day or an eight-day, whatever your custom, may it be for you and your family a Chag Sameach.