So there are wonderful coincidences. When Muslims complete their fast of Ramadan with the feast of Eid ul-Fitr, African-Americans who celebrate Kwanzaa will be observing their first day, and Jews will be lighting candles for the sixth night of Hanukkah. And it will be the day after Christmas. Christmas, Ramadan, Hanukkah, and Kwanzaa all overlap in a complicated dance of light and darkness, sun and moon. To add to the spectacle, on December 25, a rare partial solar eclipse will be visible, if the skies are clear, from nearly all regions of North America. A solar eclipse won't happen again on Christmas Day for more than three centuries.
The calendars of the three major Western religions, Judaism, Christianity, and Islam, have their amazing synchronicities and strange calculations (strange each to each). They differ on how they calculate time: The Christian and secular calendar is purely solar; the Islamic calendar is purely lunar; the Jewish calendar splits the difference--it is lunar and solar, or lunisolar.
The traditions differ on when a day begins (sunset to Jews and Muslims, midnight to Christians and seculars). They differ when the month begins--the new moon for Jews and Muslims, and no moon or no care for the phases of the moon in the Christian and secular calendars.
This year is rare, because the month of Ramadan has come to visit--so to speak--and it will not return to this exact configuration any time soon. The Islamic calendar is purely lunar, 12 months of alternating 29 and 30 days--a year that comes approximately 11 days short of the solar year. So the month of Ramadan will drift 11 days (or so) back toward November next year, and another 11 days the year after that, leaving the season of winter beyond, moving toward autumn, then summer, then spring.
It will be 33 years before Ramadan comes back to December again. But that year, Ramadan and Chanukah will miss Christmas by a whisker--Chanukah will end on Christmas Eve in 2033. It looks like we'll have to wait until 2065 for this triple overlap to occur once again.
This number too may not be entirely a coincidence. According to the Encyclopedia Judaica, Hanukkah was declared on the 25th of Kislev in remembrance of--and triumph over--the decree of Antiochus, the Greek Syrian ruler who desecrated the Temple of Jerusalem, thereby sparking the Maccabeean revolt. Some scholars speculate that that date was a pagan celebration--that Antiochus was imposing pagan rites on Jerusalem. The Maccabees turned that around and used the same date to commemorate their cleansing of the Temple and its rededication. (Hanukkah means "dedication.")
Other scholars believe that the 25th of December was also a pagan holiday. According to Britain's great monk the venerable Bede, it was "mother's night." Others believe it was a pagan festival known as the "sun's birthday"--the sun was understood to be born during the darkest days of the year. If so, then the celebration of the birth of the Son was instituted to replace the birthday of the Sun. That's something to think about in this year of solar eclipse Christmas-- which will make the darkness even darker.