The Hebrew and Gregorian calendars are supposed to synch up every 19 years.
So in theory this year's birthday should have both my Hebrew and secular birthdays on the same day. Except it doesn't. It's off by a day.
If you go to kaluach.net and look at December 15th, 1971 it says it's the third light of Chanukah.
If you look at December 15th, 1990 AND 2009 however, it says it's the fourth light of Chanukah.
I know that some years the month of Cheshvan has 30 days and other years it has 29 days.
It had 30 days both in 1971 and 2009. And 29 days in 1990.
So... anyone know why my birthdays don't line up?