Chanukah on Thanksgiving

Thanksgiving this year fell out less than a week before the start of Chanukah and that got me thinking: Have Thanksgiving and Chanukah ever coincided? At first, I tried this nifty online tool: http://stevemorse.org/jcal/whendid.html but the problem is that the date of Thanksgiving has changed (see Wikipedia):

• From 1863-1938 Thanksgiving was on the last Thursday of November
• From 1939-1941 Thanksgiving was on the 4th, 3rd and 3rd Thursdays for some of the country ("Democratic Thanksgiving"), and on the last Thursdays for other parts ("Republican Thanksgiving").
• From 1942-current Thanksgiving is on the 4th Thursday of November for almost the entire country (execpt Texas, which still celebrated "Republican Thanksgiving" in 1956)

So I whipped together a quick Mathematica notebook to do it (you can download it here). If you want to skip to the results, you can skip this whole description:
Basically, after assembling all the Thanksgiving dates in a list thanksgivings, I used the CalendarChange function to map them from Gregorian dates to dates in the Jewish calendar:

jewishdate = CalendarChange[#, Gregorian, Jewish] & /@ thanksgivings;

Then, I calculated the number of days between Thanksgiving and the first day of Chanuka (note, that Mathematica uses the Biblical month numbering system: Nisan is 1, Tishrei is 7, Kislev is 9, etc.)

daysbetween = DaysBetween[{#[[1]], 9, 25}, #, Calendar -> Jewish] & /@ jewishdate

and extracted the dates corresponding to non-negative days between:

coincideJewishDate = Extract[jewishdate, Position[daysbetween, _?NonNegative]]

which can easily be mapped back to Gregorian dates:

coincideGregorianDate = CalendarChange[#, Jewish, Gregorian] & /@ coincideJewishDate

I did the same thing, to see when the first night of Chanuka ({year,9,24}) falls out on Thanksgiving.


So, enough technobabble, here are the results of when Thanksgiving falls out relative to Chanukah.

1888	First Day
1899	Fourth Day
1918	First Night
1945*	First Night
1956*	First Day
2013	First Day
2070	First Night
2165	First Night

The two *ed years correspond to Republican Thanksgivings. So, in Texas 1945, Chanukah started the evening of Thanksgiving, and "Black Friday" was the first day of the holiday.

Also, these are the only predictable times it will ever happen. The Jewish calendar drifts around 4.3 days later every 1000 years, and I checked dates for next 10,000+ years. Chanukah does not even fall out in November after 2887. At some point [definitely by the year 15115, when Passover falls out in the summer] the Jewish calendar will need to be corrected/replaced; until such a time these are the date.

So, in 2013 Chanukah and Thanksgiving will fall out on the same day! Ladies and gentlemen, when, in three years, lots of people start talking about this incredibly rare occurrence, remember: You saw it here first!