Why does Chanukah fall on different calender days every year, but still occur towards the end of the Western calender? If Chanukah is based on the Jewish calender, shouldn’t it occur in July or February sometimes, as the calenders circle through each other?
ANSWER PERSON RESPONDS: This involves complex astronomy and religious history, so I’ll only attempt a crude uneducated simplification here.
The issue revolves around the fact that the Jewish calendar has aspects that are lunar (months) as well as solar (year). The Gregorian calendar is purely solar (the months don’t always start with the same phase of the moon). There are 12 lunar months, but these add up to less than a full solar year, so every few years an extra month needs to be added during a leap year. This is apparently specifically to keep each month in the same season each year; otherwise, each month would start 11 days earlier each year and the holidays would end up in different seasons after a while, which I think is what you’re asking about.
I’m not sure what you mean when you say “the calenders circle through each other.” Because of the extra month during the Jewish calendar leap years, it and the Gregorian calendar will approximately get back in synch every few years. Chanukah always falls on the 25th day of the month of Kislev, which will always put it at about the same time of the year (I believe late fall, before the winter solstice). As you know, from year to year the calendars aren’t at all in synch, so Chanukah of course won’t be on the same Gregorian calendar day each year.
For details and more information you should consult one of the reference sources in the Divinity School Library or Perkins Library, such as Encyclopaedia Judaica. Look under entries relating to the calendar. There are also some online sources good for quick reference, such as the entry under “Hebrew Calendar” at Wikipedia: http://en.wikipedia.org/wiki/Hebrew_calendar