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Leap year starting on Friday

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File:2016 calendar.svg
2016 is a leap year starting on Friday

Template:Short description A leap year starting on Friday is any year with 366 days (i.e. it includes 29 February) that begins on Friday 1 January and ends on Saturday 31 December. Its dominical letters hence are CB. The most recent year of such kind was 2016, and the next one will be 2044 in the Gregorian calendar<ref name="math">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> or, likewise, 2000 and 2028 in the obsolete Julian calendar.

Any leap year that starts on Friday has only one Friday the 13th: the only one in this leap year occurs in May. Common years starting on Saturday share this characteristic. This is also the only year in which February has five Mondays, as the leap day adds that extra Monday.

This year has two months (May and October) which begin on a weekend-day. Since at least one month begins on each day of the week in all years, this is the fewest possible number of months to begin on a weekend-day in a given year; this also occurs in a common year starting on Friday, in which case the two months are May and August.



CalendarsEdit

{{#if: 

 |{{calendar/{{{1}}}
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       |{{calendar/{{#ifeq:Template:Title without disambig|{{#time:Y|Template:Title without disambig}}
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           }}
          |row=|col=4
          |title=Calendar for any leap year starting on Friday,
presented as common in many English-speaking areas
          |year=2016
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}}

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 |{{calendar/{{{1}}}
    |year=2016
    |base={{#titleparts:Template:Title without disambig|2}}
    |sub={{#titleparts:Template:Title without disambig/XXX|1|3}}
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             |F={{#ifeq:off|with month|F Y|F}}
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           }}
          |row=3|col=4
          |title=ISO 8601-conformant calendar with week numbers for
any leap year starting on Friday (dominical letter CB)
          |year=2016
          |show_year={{#ifeq:Template:Title without disambig|{{#time:F Y|Template:Title without disambig}}|off|on}}
          |F={{#ifeq:Template:Title without disambig|{{#time:F Y|Template:Title without disambig}}|F Y|F}}
          |float=right
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  }}

}}

Applicable yearsEdit

Gregorian CalendarEdit

Leap years that begin on Friday, along with those starting on Sunday, occur most frequently: 15 of the 97 (≈ 15.46%) total leap years in a 400-year cycle of the Gregorian calendar. Thus, their overall occurrence is 3.75% (15 out of 400).

For this kind of year, the ISO week 10 (which begins March 7) and all subsequent ISO weeks occur later than in all other leap years.

Gregorian leap years starting on Friday<ref name=math/>
Decade 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th
16th century prior to first adoption (proleptic) 1588
17th century 1616 1644 1672
18th century 1712 1740 1768 1796
19th century 1808 1836 1864 1892
20th century 1904 1932 1960 1988
21st century 2016 2044 2072
22nd century 2112 2140 2168 2196
23rd century 2208 2236 2264 2292
24th century 2304 2332 2360 2388
25th century 2416 2444 2472
26th century 2512 2540 2568 2596
400-year cycle
0–99 16 44 72
100–199 112 140 168 196
200–299 208 236 264 292
300–399 304 332 360 388

Julian CalendarEdit

Like all leap year types, the one starting with 1 January on a Friday occurs exactly once in a 28-year cycle in the Julian calendar, i.e. in 3.57% of years. 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).

Julian leap years starting on Friday
Decade 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th
15th century 1412 1440 1468 1496
16th century 1524 1552 1580
17th century 1608 1636 1664 1692
18th century 1720 1748 1776
19th century 1804 1832 1860 1888
20th century 1916 1944 1972 2000
21st century 2028 2056 2084
22nd century 2112 2140 2168 2196

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HolidaysEdit

InternationalEdit

Roman Catholic SolemnitiesEdit

Australia and New ZealandEdit

British IslesEdit

CanadaEdit

United StatesEdit

ReferencesEdit

Template:Reflist Template:Navbox top

Year starts Common years Leap years
1 Jan Count Ratio 31 Dec DL DD Count Ratio 31 Dec DL DD Count Ratio
Sun 58 14.50 % Sun A Tue 43 10.75 % Mon AG Wed 15 Template:03.75 %
Mon 56 14.00 % Mon G Wed 43 10.75 % Tue GF Thu 13 Template:03.25 %
Tue 58 14.50 % Tue F Thu 44 11.00 % Wed FE Fri 14 Template:03.50 %
Wed 57 14.25 % Wed E Fri 43 10.75 % Thu ED Sat 14 Template:03.50 %
Thu 57 14.25 % Thu D Sat 44 11.00 % Fri DC Sun 13 Template:03.25 %
Fri 58 14.50 % Fri C Sun 43 10.75 % Sat CB Mon 15 Template:03.75 %
Sat 56 14.00 % Sat B Mon 43 10.75 % Sun BA Tue 13 Template:03.25 %
∑ 400 100.0 % 303 75.75 % 97 24.25 %

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