Rabbi Milder of Beth Emek in Pleasanton shared the following thoughts with his congregation on the overlap of Christmas and Hanukkah this year. He doesn’t just explain how it is that the two holidays can overlap one year but not the next, he explains the different calendars. It’s some pretty useful information. As Americans we often forget that the calendar we use is not really a secular calendar, but rather a Christian calendar that is named after Pope Gregory XIII, who introduced it in 1582.
When Hanukkah and Christmas Coincide
Okay, this doesn’t happen very often. The first night of Hanukkah happens to fall on Christmas eve this year, December 24.
How unusual? It won’t happen again until 2027, and then it won’t come up again until 2073!
Of course, Hanukkah and Christmas overlap every few years, but the confluence of the beginning of the Jewish and Christian holiday is fairly rare.
Why is that? The holidays operate on two different calendars, and there is no relationship between the two. Even though Chanukah begins on the 25th of Kislev, and Christmas on the 25th of December, the months of Kislev and December have nothing to do with one another.
The calendar that we commonly think of as the secular calendar (on which today happens to be December 23, 2016) is actually a Christian calendar, known as the Gregorian calendar. It is based on the solar cycle, i.e. it has 365 days a year, plus a correction every four years to make up for the actual solar cycle. If there are 9 hours and 33 minutes of daylight today, next year on December 23 there will also be 9 hours and 33 minutes of daylight.
The Jewish calendar, however, is a lunar-solar calendar. Every month is a lunar month, with the first day being the new moon. Hanukkah will always begin on a waning crescent moon, near the end of the month of Kislev. Gregorian months, by contrast, have nothing to do with the moon.
Since a lunar month is either 29 or 30 days long, while the Gregorian months are 30 or 31 days long, twelve Jewish months wind up being about 12 days shorter than the Gregorian year. The Jewish calendar, therefore, has a correction to get it back in sync with the solar year. That correction is an extra month (Adar I), which gets inserted every two or three years.
For the next couple of years, Hanukkah will move earlier and earlier in December, until we add a leap month, which will push Hanukkah into late December again. The pattern keeps repeating, but the exact days of the respective months don’t sync up very often.
Wondrous? Fascinating? Yes, particularly if you like math and astronomy.
There is a lot to admire and appreciate about the holidays celebrated by other faiths. That Christmas and Hanukkah begin at the same time this year gives us pause to consider what we have to learn from one another. We may not believe the same things, but like the sun and the moon, we are in a kind of dance that goes round and round, shining light each in our own way.
Here’s to the alignment of our cosmic lights!
Rabbi Larry Milder