:Leap year starting on Friday

{{Short description|none}}

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{{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 |access-date=20 July 2017}} 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.

Calendars

{{calendar|year=2016|show_year=off|title=Calendar for any leap year starting on Friday,
presented as common in many English-speaking areas}}

{{calendar|year=2016|show_year=off|format=iso|row=3|zero=0|title=ISO 8601-conformant calendar with week numbers for
any leap year starting on Friday (dominical letter CB)}}

Applicable years

= Gregorian Calendar =

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.

class="wikitable"

|+ Gregorian leap years starting on Friday

!scope=row| Decade

! 1st !! 2nd !! 3rd !! 4th !! 5th !! 6th !! 7th !! 8th !! 9th !! 10th

style="opacity: 0.5;"

! style="background-color:#efefef;" | 16th century

| colspan="8" | prior to first adoption (proleptic)

1588
17th century

|

|1616

|

|

|1644

|

|

|1672

|

|

style="background-color:#efefef;" | 18th century

| || 1712 || || 1740 || || || 1768 || || || 1796

style="background-color:#efefef;" | 19th century

| 1808 || || || 1836 || || || 1864 || || || 1892

style="background-color:#efefef;" | 20th century

| 1904 || || || 1932 || || 1960 || || || 1988 ||

style="background-color:#efefef;" | 21st century

| || 2016 || || || 2044 || || || 2072 || ||

style="background-color:#efefef;" | 22nd century

| || 2112 || || 2140 || || || 2168 || || || 2196

style="background-color:#efefef;" | 23rd century

| 2208 || || || 2236 || || || 2264 || || || 2292

style="background-color:#efefef;" | 24th century

| 2304 || || || 2332 || || 2360 || || || 2388 ||

style="background-color:#efefef;" | 25th century

| || 2416 || || || 2444 || || || 2472 || ||

style="background-color:#efefef;" | 26th century

| || 2512 || || 2540 || || || 2568 || || || 2596

class="wikitable"

|+ 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 Calendar =

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).

class="wikitable"

|+ Julian leap years starting on Friday

!scope=row| Decade

! 1st !! 2nd !! 3rd !! 4th !! 5th !! 6th !! 7th !! 8th !! 9th !! 10th

style="background-color:#efefef;" | 15th century

| || 1412 || || 1440 || || || 1468 || || || 1496

style="background-color:#efefef;" | 16th century

| || || 1524 || || || 1552 || || 1580 || ||

style="background-color:#efefef;" | 17th century

| 1608 || || || 1636 || || || 1664 || || || 1692

style="background-color:#efefef;" | 18th century

| || 1720 || || || 1748 || || || 1776 || ||

style="background-color:#efefef;" | 19th century

| 1804 || || || 1832 || || 1860 || || || 1888 ||

style="background-color:#efefef;" | 20th century

| || 1916 || || || 1944 || || || 1972 || || 2000

style="background-color:#efefef;" | 21st century

| || || 2028 || || || 2056 || || || 2084 ||

style="background-color:#efefef;" | 22nd century

| || 2112 || || 2140 || || || 2168 || || || 2196

{{Commons category}}

Holidays

= International =

= Roman Catholic Solemnities =

= Australia and New Zealand =

= British Isles =

= Canada =

= United States =

References

{{Reflist}}

{{List of calendars}}

{{DEFAULTSORT:Leap Year Starting On Friday}}

Category:Gregorian calendar

Category:Julian calendar

Category:Friday