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Calendar, in the present context, refers to the Gregorian calendar, because it is the one used most frequently, worldwide. In a Gregorian calendar, centuries are not leap years unless divisible by 400 (Eg: The year 2000 is a leap year, whereas 1900 isn’t).
As in the picture below, there can be only 14 calendar patterns - 1 to 14 (Years starting from Sunday to Saturday, either leap or non-leap year). Any calendar repeats in a minimum gap of 6 years and a maximum gap of 40 years. All the patterns 1 to 14 occur at least once in a minimum span of 25 years (Eg: 2000 - 2024) and a maximum span of 40 (Eg: 1889 - 1928).
1. Repetition in the succeeding years:
I. Calendars of non-leap years:
A. Calendars of non-leap years of the form 4n and 4n+1 repeat after 6 years. Eg: Calendar of the year 1900 repeats in 1906; that of 2017 repeats in 2023.
B. Calendars of non-leap years of the form 4n+2 and 4n+3 repeat after 11 years. Eg: Calendar of the year 2018 repeats in 2029; that of 2019 in 2030.
Exception: The years of the 90s of a century ending in a non-leap year do not follow this pattern. Calendar of such a year Y repeats after
(a) 12 years, if Y ∈ {90, 91, 97, 98}
Eg: Calendar of the year 1890 repeats in 1902.
(b) 6 years, if Y ∈ {93, 94, 95, 99}
Eg: Calendar of the year 1895 repeats in 1901.
II. Calendars of leap years:
Calendar of a leap year repeats after
A. 40 years, in the 70s and 80s of a century ending in a non-leap year.
Eg: Calendar of the year 1872 repeats in 1912.
B. 12 years, in the 90s of a century ending in a non-leap year.
Eg: Calendar of the year 1892 repeats in 1904.
C. 28 years, otherwise.
Eg: Calendar of the year 2020 repeats in 2048.
Note: Combining I and II, this is the order of repetition of calendars of the 90s of a century ending in a non-leap year:
12 12 12 6 6 6 12 12 12 6
2. Occurrence in the preceding years:
I. Calendars of non-leap years:
A. Calendars of non-leap years of the form 4n and 4n+3 are the same as that of the 6th preceding year. Eg: Calendar of the year 1900 is the same as that of 1894; that of 2019 is the same as that of 2013.
B. Calendars of non-leap years of the form 4n+1 and 4n+2 are the same as that of the 11th preceding year. Eg: Calendar of the year 2021 is the same as that of 2010; that of 2022 is the same as that of 2011.
Exception: The first ten years of a century ending in a leap year do not follow this pattern. Calendar of such a year Y is the same as that of
(a) the 6th preceding year, if Y ∈ {01, 05, 06, 07}
Eg: Calendar of the year 1905 is the same as that of 1899.
(b) the 12th preceding year, if Y ∈ {02, 03, 09, 10}
Eg: Calendar of the year 1910 is the same as that of 1898.
II. Calendars of leap years:
Calendar of a leap year is the same as that of
A. the 40th preceding year, in the second and third decade of a century ending in a leap year. Eg: Calendar of the year 1916 is the same as that of 1876.
B. the 12th preceding year, in the first decade of a century ending in a leap year. Eg: Calendar of the year 1908 is the same as that of 1896.
C. the 28th preceding year, otherwise. Eg: Calendar of the year 2024 is the same as that of 1996.
Note: Combining I and II, this is the order of the immediate preceding years in which calendars of the first decade (01-10) of a century ending in a leap year, are the same:
6 12 12 12 6 6 6 12 12 12
What else can I help you with?
How often do years repeat calendars?
it depends if you add leap years
How often years repeat?
.d.o.n.t.k.n.o.w
When will the calendar of 1998 repeat?
The calendar of 1998 will repeat in the year 2029. This is because there is a 11-year cycle for calendars to repeat. In this cycle, the days of the week for a particular date will match up again after 11 years. Therefore, the calendar of 1998 will align with the calendar of 2029.
When will 2002 calendar year repeat?
Well, sweetheart, the calendar year 2002 will repeat exactly 11 years after it originally happened. So, mark your calendars for the year 2013 because that's when you'll get to relive all the early 2000s nostalgia. But hey, who's counting anyway?
Where can you find a listing of the years in the 14 calendars that cover all years?
The Gregorian calendar repeats every eleven years not fourteen !
How often do years repeat calendars?
it depends if you add leap years
When will the 2000 calendar repeat?
The 2000 calendar will repeat in 2028. This was a leap year and leap year calendars generally repeat every 28 years.
What years do calendars repeat with the same day-date combinations as 2009?
Taking the rest of the 21st century, 2009 repeats its day/date combination in 2015, 2026, 2037, 2043, 2054, 2065, 2071, 2082, 2093 and 2099.
Why do certain calendars repeat after 50 years - 2017 will have the same day-date arrangement as 1967?
Calendar years repeat more often than that and not every year will repeat 50 years later. 2013 and 2063 have different arrangements for example. A year can repeat after 5 years, after 6 years or after 11 years. It will depend on when the leap years are in relation to the year you are referring to. 1967 repeated in 1978, 1989, 1995, 2006 and will again in 2017.
When will the 1976 calendar repeat itself?
Since 1976, it only repeated in 2004 and will next repeat in 2032. It was a leap year and leap year calendars generally repeat every 28 years.
When was the last calendar equal to 2012?
Because of the extra weekday each year, and because of leap years, identical non-leap year calendars repeat on a cycle of 6 or 11 years. Leap years repeat every 28 years. (There are only 14 different possible calendars.) The years that were the same calendar as 2012 were 1984, 1956, and 1928.
How often years repeat?
.d.o.n.t.k.n.o.w
Is 2010 calendar a repeat from the past?
Yes. All calendars repeat. Taking just from the start of the 20th century, the following years had the same calendar as 2010 did: 1909, 1915, 1926, 1937, 1943, 1954, 1965, 1971, 1982, 1993 and 1999. It will repeat again in 2021.
Why did 1911 have the same calendar as 1893 - calendars do not normally repeat after 18 years?
Because 1900 was not a leap year, so that would have affected that period and thrown things out by a day.
Can you reuse a 2004 calendar again in 2015 - since people have said that calendars repeat every 11 years?
No. 2004 was a leap year, but 2015 is not. It is not always the case that a calendar repeats every 11 years.
When would a 2009 calendar be usable again?
Calendars do actually repeat in a certain pattern. If the year is not a leap year, then the calendar will repeat in 11 years, so a 2009 calendar would again be usable in the year 2020.
When will 1977 calendar repeat?
Oh, dude, the 1977 calendar will repeat in 2023. Like, calendars repeat every 28 years because that's how long it takes for the days of the week to line up again. So, if you're planning a '70s-themed party, you might want to mark your calendar for 2023!
