Other Facts and Information



Days Per Month Reckoning
  A: The Current Actual Reckoning

     January - 31                            July - 31
     February - 28 (29 in leap year)         August - 31
     March - 31                              September - 30
     April - 30                              October - 31
     May - 31                                November - 30
     June - 30                               December - 31


     Regular Year - 365 days ... 52 7-day weeks plus 1 day

     Leap Year - 366 days ... 52 7-day weeks plus 2 days

     Halves - 181 (182) / 184  |  Quarters - 90 (91) / 91 / 92 / 92


     Leap Year - February 29th

     Leap Year is any year that is divisble by 4. The exception to this is that
     any century year that is -NOT- divisible by 400 (1700, 1800, 1900, 2100,
     2200, etc) will not be a Leap Year. Century Years that are divisible by
     400 (1600, 2000, 2400, 2800, etc) will be Leap Years.

     In any 400-year period, there are 303 365-day regular years (110,595 days)
     and 97 366-day Leap Years (35,502 days). This makes for a total of 146,097
     days (exactly 20,871 7-day weeks) during the 400-year period.

     400-Year Periods - Saturday January 1st 1600 to Friday December 31st 1999

                        Saturday January 1st 2000 to Friday December 31st 2399



  B: This Author's 364/371 Days Alternative Reckoning

     January, April, July and October - 30 days each. 1st day of each month is Sunday
     
     February, May, August and November - 31 days each. 1st of each month is Tuesday

     March, June, September and December - 30 days each. 1st day of each month is Friday


     Regular Year - 364 days ... 52 7-day weeks  |  Leap Year - 371 days ... 53 7-day weeks

     Halves - 182 / 182  |  Quarters - 91 / 91 / 91 / 91


     Leap Year - a full 7-day "Leap Week" between June 30 and July 1st

     Leap Year is any year that ends in "0" or "5", with the following exceptions ...

       (1) Any years ending in "25" or "75"

       (2) Any Century Years divisible by 400 (1600, 2000, 2400, 2800, etc.)

     In any 400-year period, there are 329 364-day regular years (119,756 days)
     and 71 371-day Leap Years (26,341 days). This makes for a total of 146,097
     days (exactly 20,871 7-day weeks) during the 400-year period.



  C: An Alternative Reckoning, proposed at this site - The Symmetry 454 Calendar

     January - 28                            July - 28
     February - 35                           August - 35
     March - 28                              September - 28            
     April - 28                              October - 28
     May - 35                                November - 35
     June - 28                               December - 28 (35)


     Regular Year - 364 days ... 52 7-day weeks  |  Leap Year - 371 days ... 53 7-day weeks

     Halves - 182 / 182 (189)  |  Quarters - 91 / 91 / 91 / 91 (98)


     Every 7-day week always begins on Monday and always ends on Sunday. The 13th day of any
     month would always be on Saturday, rather than Friday (Sorry about that, Jason!).

     LEAP YEAR occurs rvery five to six years  (cycles of 6 + 5 -OR- 6 + 6 + 5) using special
     a formula. "Leap Week" is achieved by making December a 35-day month.

     Here's an alternative Leap Year idea suggested by the Symmetry 454 site -- Rather than a
     35-day December, "Leap Week" could be celebrated as a special seven-day week all to itself.
     The Symmetry 454 site suggests that the "Leap Week" could occur after December 28. The author
     of this page (Information About Perpetual Calendar) suggests placing the Leap Week between
     June 28 and July 1.





The 4000 Year Rule
  It has been suggested by some observers, including astronomer John Herschel (1792-1871), that a better approximation to
  the length of the tropical year would be 365 969/4000 days = 365.24225 days.  This would dictate 969 leap years every
  4000 years, rather than the 970 leap years mandated by the Gregorian calendar. This could be achieved by not observing
  February 29th in the years 4000 AD, 8000 AD, 12000 AD and so on. In other words, any year divisible by 4000 would not
  be observed as a Leap Year.

  To date, this "4000-year rule" has not been officially adopted.              

SEE ALSO:
Introduction Page          Was it really necessary to drop those 10 days in 1582?          External Links


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