Each row in the tables below represents one of the 14 possible year layouts. Each
column is headed with the name of the month and the number of days in it.
The days of the week in the body of the table
correspond to the first day of that month. So, taking the first possibility as
an example: if January starts on a Sunday, February must start on a Wednesday and so on.
The possibilities are broken into two groups of seven: the first for non-leap years (February has
28 days in a non-leap year) and the second group is for leap years (February has 29 days in
a leap year)
Non Leap Years
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
-31 -28 -31 -30 -31 -30 -31 -31 -30 -31 -30 -31
Sun Wed Wed Sat Mon Thu Sat Tue Fri Sun Wed Fri
Mon Thu Thu Sun Tue Fri Sun Wed Sat Mon Thu Sat
Tue Fri Fri Mon Wed Sat Mon Thu Sun Tue Fri Sun
Wed Sat Sat Tue Thu Sun Tue Fri Mon Wed Sat Mon
Thu Sun Sun Wed Fri Mon Wed Sat Tue Thu Sun Tue
Fri Mon Mon Thu Sat Tue Thu Sun Wed Fri Mon Wed
Sat Tue Tue Fri Sun Wed Fri Mon Thu Sat Tue Thu
Leap Years
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
-31 -29 -31 -30 -31 -30 -31 -31 -30 -31 -30 -31
Sun Wed Thu Sun Tue Fri Sun Wed Sat Mon Thu Sat
Mon Thu Fri Mon Wed Sat Mon Thu Sun Tue Fri Sun
Tue Fri Sat Tue Thu Sun Tue Fri Mon Wed Sat Mon
Wed Sat Sun Wed Fri Mon Wed Sat Tue Thu Sun Tue
Thu Sun Mon Thu Sat Tue Thu Sun Wed Fri Mon Wed
Fri Mon Tue Fri Sun Wed Fri Mon Thu Sat Tue Thu
Sat Tue Wed Sat Mon Thu Sat Tue Fri Sun Wed Fri
Year layouts have some interesting patterns:
In non
leap years, the years always begin and end on the same day of the week.
January has the identical calendar (starts on the same day and has the same number of days) with
another month each and every year: either with July or with October. No other months share identical
layouts in any given year.
During non leap years, February, March and November always start on the same day of the week.
The months of May and June are the only months that never share the same starting day with another month
regardless if it is a leap year or not. October fails to share the starting day with other months, but
only in leap years.
