A weekly feature of Torah Tidbits to help clarify practical and conceptual aspects of the Jewish Calendar, thereby better fulfilling the mitzva of HaChodesh HaZeh Lachem...
This is one of those Shabbatot that are neither M'vorchim nor in the active Kiddush L'vana part of the month, so let's use it for other calendar issues.
"Wow, Pesach is late this year!" "Hey, Rosh HaShana is going to be October 4th and 5th - so late." Same comment, of course. (The proper wise guy retort to these and similar comments is, Pesach is exactly on time - 15 Nissan, just like it is every year. It is April that's early.)
But the "real" answer in general is that dates following a second Adar will be on the late side. Specifically, among the 7 years within a 19 year Lunar cycle (being years 3,6,8,11,14,17,19), it is the 8th year that throws dates the latest. 5765 is the 8th year of the current cycle. Counting this year, there have been 5 two-Adar years within the last 11 years. If you take any other 13- month year as a starting point and count backwards, you will find 5 two-Adar years within the past 12 years. Every 12-month year makes the Hebrew dates coming up approx. 11 days earlier, in relation to the secular calendar. Every 13-month year makes the Hebrew dates approx. 19 days later. If you think it out, you will see that during the 8th year in a cycle, after both Adars, the coming dates will be roughly the latest they ever get.
However, this year is a CHASEIR, meaning that Cheshvan and Kislev both had 29 days. If the 8th year of a cycle is K'SEIDER (29/30) or even more so, SHALEIM (30/30), then the upcoming Pesach, for example, will be even a day or two later. Of course, the status of Cheshvan and Kislev of the previous years will also affect how late Pesach will be. That is a much more difficult pattern to factor in to our simplified explanation. And the number of recent February 29ths also affects the secular date of Pesach (in our example).
Let's take a look if any of
this matches reality. This year, the Seder will be on Motza'ei Shabbat,
April 23rd. Last year it was April 5th. Expected to be earlier because 5764
was not a M'UBERET. The year before, it was April 16th. Late, but not as
late as this year. 5760, year 3 of the current cycle, Seder was April 19th -
late, but still not as late as this year. 5757 was the 19th year of the
previous cycle. April 21st. Still not as late as this year. Going back year
by year, finds Seder bouncing around the end of March and beginning of
April. Back in 5746 (the 8th year of the previous cycle), it was on April
23rd, like this year. 19 years earlier, in 5727 (right before the Six Days
War), Seder was April 24th. Both Cheshvan and Kislev had 30 days that year.
Which helps explain the extra day later, compared with this year.