The First Night of Hanukkah will be on Thanksgiving this Year.


This has never happened before.


Thanksgiving is set as the fourth Thursday in November, meaning the latest it can be is 11/28. 11/28 is also the earliest Hanukkah can be.
The Jewish calendar repeats on a 19 year cycle, and Thanksgiving 
repeats on a 7 year cycle. You would therefore expect them to coincide
 roughly every 19×7 = 133 years. Looking back, this is approximately
 correct – the last time it would have happened is 1861. However,
 Thanksgiving was only formally established by President Lincoln in
1863. So, it has never happened before.



Why won’t it ever happen again?


The reason is because the Jewish calendar is very slowly getting out of sync with the solar calendar, at a rate of 4 days per 1000 years.
This means that while presently Hanukkah can be as early as 11/28, 
over the years the calendar will drift forward, such that the earliest
 Hanukkah can be is 11/29. The next time Hanukkah falls on 11/28 is 
2146, which is a Monday. Therefore, 2013 is the only time Hanukkah 
will ever overlap with Thanksgiving.  

Of course, if the Jewish calendar is never modified in any way, then it will slowly move forward through the Gregorian calendar, until it
 loops all the way back to where it is now. So, Hanukkah would again 
fall on Thursday, 11/28…in the year 79,811. Given our trajectory it is fair to say humans won’t be here then. And
 if there are no humans, the holidays will be cancelled.



So on November 28th 2013, enjoy your turkey and your latkes. It has
 never happened before, and it will never happen again.