{{Short description|Type of year B on a solar calendar according to its starting and ending days in the week}}
{{Short description|Type of year B on a solar calendar according to its starting and ending days in the week}}
A '''common year starting on Saturday''' is any non-[[leap year]] (i.e. a year with 365 days) that begins on [[Saturday]], 1 January, and ends on Saturday, 31 December. Its [[dominical letter]] hence is '''B'''. The most recent year of such kind was [[2022]] and the next one will be [[2033]] in the Gregorian calendar<ref name="math">{{cite web|url=https://webspace.science.uu.nl/~gent0113/calendar/isocalendar.htm |author=Robert van Gent |title=The Mathematics of the ISO 8601 Calendar |publisher=Utrecht University, Department of Mathematics |date=2017 |accessdate=20 July 2017}}</ref> or, likewise, [[2023]] and [[2034]] in the obsolete [[Julian calendar]]. See [[#Applicable years|below for more]].
A '''common year starting on Saturday''' is any non-[[leap year]] (i.e. a year with 365 days) that begins on [[Saturday]], 1 January, and ends on Saturday, 31 December. Its [[dominical letter]] hence is '''B'''. The most recent years of such kind was [[2011]] and [[2022]] and the next one will be [[2033]] in the Gregorian calendar<ref name="math">{{cite web|url=https://webspace.science.uu.nl/~gent0113/calendar/isocalendar.htm |author=Robert van Gent |title=The Mathematics of the ISO 8601 Calendar |publisher=Utrecht University, Department of Mathematics |date=2017 |accessdate=20 July 2017}}</ref> or, likewise, [[2023]] and [[2034]] in the obsolete [[Julian calendar]]. See [[#Applicable years|below for more]].
Any common year that [[common year starting on Wednesday|starts on Wednesday]], [[common year starting on Friday|Friday]] or [[Saturday]] has only one [[Friday the 13th]]: the only one in this common year [[May 13|occurs in May]]. [[Leap year starting on Friday|Leap years starting on Friday]] share this characteristic.
Any common year that [[common year starting on Wednesday|starts on Wednesday]], [[common year starting on Friday|Friday]] or [[Saturday]] has only one [[Friday the 13th]]: the only one in this common year [[May 13|occurs in May]]. [[Leap year starting on Friday|Leap years starting on Friday]] share this characteristic.
Revision as of 15:35, 19 April 2024
Type of year B on a solar calendar according to its starting and ending days in the week
A common year starting on Saturday is any non-leap year (i.e. a year with 365 days) that begins on Saturday, 1 January, and ends on Saturday, 31 December. Its dominical letter hence is B. The most recent years of such kind was 2011 and 2022 and the next one will be 2033 in the Gregorian calendar[1] or, likewise, 2023 and 2034 in the obsolete Julian calendar. See below for more.
In the (currently used) Gregorian calendar, alongside Sunday, Monday, Wednesday or Friday, the fourteen types of year (seven common, seven leap) repeat in a 400-year cycle (20871 weeks). Forty-three common years per cycle or exactly 10.75% start on a Saturday. The 28-year sub-cycle will break at a century year which is not divisible by 400 (e.g. it broke at the year 1900 but not at the year 2000).
In the now-obsolete Julian calendar, the fourteen types of year (seven common, seven leap) repeat in a 28-year cycle (1461 weeks). A leap year has two adjoining dominical letters, (one for January and February and the other for March to December in the Church of England, as 29 February has no letter). Each of the seven two-letter sequences occurs once within a cycle, and every common letter thrice.
As the Julian calendar repeats after 28 years that means it will also repeat after 700 years, i.e. 25 cycles. The year's position in the cycle is given by the formula (((year + 8) mod 28) + 1). Years 10, 16 and 27 of the cycle are common years beginning on Saturday. 2017 is year 10 of the cycle. Approximately 10.71% of all years are common years beginning on Saturday.
Mother's Day falls on its earliest possible date, May 8. This is the only type of year when Presidents’ Day to Mother’s Day are only 76 days apart. They are 83 days apart in all other years