[OC] When does Chanukah start?

Every year Jews are asked by their non-Jewish friends, "When is Chanukah?"

And most of us have no clue.

Why? The date on the Gregorian calendar changes from year-to-year! Here are the most recent (past 125 years) starting nights and dates for Chanukah. Datawrapper charts and the data from timeanddate.com.

Between the leap day every 4 years on the Gregorian calendar (except for years that are perfectly divisible by 400) and the oddities of the Jewish calendar (which uses a 19-year cycle of 12 and 13 month years), there isn't any real noticeable pattern of to be found.

However, there is some very slight drift as both calendars try to approximate the true length of a year. So if the human race makes it another few thousand years, Chanukah would start on average a few days later on the Gregorian calendar than it does now.