Leap year starting on Saturday

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A leap year starting on Saturday is any year with 366 days (i.e. it includes 29 February) that begins on Saturday, 1 January, and ends on Sunday, 31 December. Its dominical letters hence are BA. The most recent year of such kind was 2000, and the next one will be 2028 in the Gregorian calendar or, likewise 2012 and 2040 in the obsolete Julian calendar. In the Gregorian calendar, years divisible by 400 are always leap years starting on Saturday. The most recent such occurrence was 2000 and the next one will be 2400, see below for more.{{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}}

Any leap year that starts on Saturday has only one Friday the 13th: the only one in this leap year occurs in October. Common years starting on Sunday share this characteristic, but also have another in January. From August of the common year preceding that year until October in this type of year is also the longest period (14 months) that occurs without a Friday the 13th. Common years starting on Tuesday share this characteristic, from July of the year that precedes it to September in that type of year.

These types of years are the only ones which contain 54 different calendar weeks (2 partial, 52 in full) in areas of the world where Sunday is considered the first day of the week, and also the only type of year to contain 53 full weekends.

This year has four months (January, April, July and October) which begin on a weekend-day. This is also the only type of leap year in which the first and last day of the calendar year fall on weekend-days.

Calendars

{{calendar|year=2000|show_year=off|title=Calendar for any leap year starting on Saturday,
presented as common in many English-speaking areas}}

{{calendar|year=2000|show_year=off|format=iso|row=3|zero=0|title=ISO 8601-conformant calendar with week numbers for
any leap year starting on Saturday (dominical letter BA)}}

Applicable years

= Gregorian Calendar =

Leap years that begin on Saturday, along with those starting on Monday and Thursday, occur least frequently: 13 out of 97 (≈ 13.402%) total leap years in a 400-year cycle of the Gregorian calendar. Their overall occurrence is thus 3.25% (13 out of 400).

class="wikitable"

|+ Gregorian leap years starting on Saturday

!scope=row| Decade

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

style="opacity: 0.5;"

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

|colspan=9| prior to first adoption (proleptic)

1600
style="background-color:#efefef;" | 17th century

| || || 1628 || || || 1656 || || || 1684 ||

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

| || || 1724 || || || 1752 || || 1780 || ||

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

| || 1820 || || || 1848 || || || 1876 || ||

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

| || || 2124 || || || 2152 || || 2180 || ||

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

| || 2220 || || || 2248 || || || 2276 || ||

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

| || 2316 || || || 2344 || || || 2372 || || 2400

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

| || || 2428 || || || 2456 || || || 2484 ||

class="wikitable"

|+ 400-year cycle

0–99

| 0 || 28 || 56 || 84

100–199

| 124 || 152 || 180 ||

200–299

| 220 || 248 || 276 ||

300–399

| 316 || 344 || 372 ||

{{List of calendars}}

= Julian Calendar =

Like all leap year types, the one starting with 1 January on a Saturday 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 Saturday

!scope=row| Decade

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

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

| || || 1424 || || || 1452 || || 1480 || ||

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

| 1508 || || || 1536 || || || 1564 || || || 1592

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

| || 1620 || || || 1648 || || || 1676 || ||

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

| 1704 || || || 1732 || || 1760 || || || 1788 ||

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

| || 1816 || || || 1844 || || || 1872 || || 1900

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

| || || 1928 || || || 1956 || || || 1984 ||

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

| || 2012 || || 2040 || || || 2068 || || || 2096

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

| || || 2124 || || || 2152 || || 2180 || ||

Holidays

= International =

= Roman Catholic Solemnities =

= Australia and New Zealand =

= British Isles =

= Canada =

= United States =

References

{{Commons category}}

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{{List of calendars}}

{{DEFAULTSORT:Leap Year Starting On Saturday}}

Category:Gregorian calendar

Category:Julian calendar

Category:Saturday