Is there a recurring pattern for calendars?

Answer 1

The calendar actually follows a 400-year cycle. Since Dec 7, 2006 is a Thursday, Dec 7, 1606 was also a Thursday.

You can even prove this. The number of days in 400 years is:

365 * 400 + 24 + 24 + 24 + 25

The three 24s and one 25 account for the leap days in each century - you don't have a leap year for a year ending in 00 unless the year is divisible by 400. Anyway, do the above calculator and you get 146,097, which is evenly divisible by 7. So, the calendar is back to the day of the week it started on.

Answer 2

Think about it. There are only seven days in a week. January 1 will fall on a Sunday OR Monday OR Tuesday...etc. The rest of the year will follow suit. Then there are Leap Years, which will throw things off by one day after February 28th, but there are only seven ways that can happen (seven days in a week that each date can fall on). So yes, there is a recurring pattern.

Answer 3

Heck Yes! There is a rotation when after a while when lets say nov. the first is on a monday, considering leap years...
if there is only one leap year than the loop to get back to monday nov. first is going to be 5 years, but if there are two than it could skip a monday...eventually it will alway go back, and if you go far enough you will see the pattern.