A common year starting on Friday is any non-
leap year
A leap year (also known as an intercalary year or bissextile year) is a calendar year that contains an additional day (or, in the case of a lunisolar calendar, a month) added to keep the calendar year synchronized with the astronomical year or ...
(i.e. a year with 365 days) that begins on
Friday
Friday is the day of the week between Thursday and Saturday. In countries that adopt the traditional "Sunday-first" convention, it is the sixth day of the week. In countries adopting the ISO-defined "Monday-first" convention, it is the fifth d ...
, 1 January, and ends on Friday, 31 December. Its
dominical letter hence is C. The most recent year of such kind was
2021 and the next one will be
2027 in the
Gregorian calendar
The Gregorian calendar is the calendar used in most parts of the world. It was introduced in October 1582 by Pope Gregory XIII as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years d ...
,
or, likewise,
2011,
2022 and
2033
The 2030s (pronounced "twenty-thirties"; shortened to the '30s) is the next decade in the Gregorian calendar that will begin on 1 January 2030, and will end on 31 December 2039.
Plans and goals
* NASA plans to execute a crewed mission to Mars be ...
in the obsolete
Julian calendar
The Julian calendar, proposed by Roman consul Julius Caesar in 46 BC, was a reform of the Roman calendar. It took effect on , by edict. It was designed with the aid of Greek mathematicians and astronomers such as Sosigenes of Alexandri ...
, see
below for more. This common year is one of the three possible common years in which a century year can begin on, and occurs in century years that
yield a remainder of 100 when divided by 400. The most recent such year was
1700 and the next one will be
2100.
Any common year that
starts on Wednesday,
Friday
Friday is the day of the week between Thursday and Saturday. In countries that adopt the traditional "Sunday-first" convention, it is the sixth day of the week. In countries adopting the ISO-defined "Monday-first" convention, it is the fifth d ...
or
Saturday
Saturday is the day of the week between Friday and Sunday. No later than the 2nd century, the Romans named Saturday ("Saturn's Day") for the planet Saturn, which controlled the first hour of that day, according to Vettius Valens. The da ...
has only one
Friday the 13th
Friday the 13th is considered an unlucky day in Western superstition. It occurs when the 13th day of the month in the Gregorian calendar falls on a Friday, which happens at least once every year but can occur up to three times in the same year. ...
: the only one in this common year
occurs in August.
Leap years starting on Thursday share this characteristic, but also have another one
in February.
In this common year, February is rectangular where weeks start on Monday,
Martin Luther King Jr. Day is on
January 18
Events Pre-1600
* 474 – Seven-year-old Leo II succeeds his maternal grandfather Leo I as Byzantine emperor. He dies ten months later.
* 532 – Nika riots in Constantinople fail.
*1126 – Emperor Huizong abdicates the Chin ...
,
Valentine’s Day is on a
Sunday
Sunday is the day of the week between Saturday and Monday. In most Western countries, Sunday is a day of rest and a part of the weekend. It is often considered the first day of the week.
For most observant adherents of Christianity, Sund ...
,
Presidents Day is on its earliest possible date,
February 15
Events Pre-1600
* 438 – Roman emperor Theodosius II publishes the law codex Codex Theodosianus
* 590 – Khosrau II is crowned king of Persia.
* 706 – Byzantine emperor Justinian II has his predecessors Leontios and Tib ...
,
St. Patrick’s Day is on a
Wednesday,
Memorial Day is on its latest possible date,
May 31,
Juneteenth is on a
Saturday
Saturday is the day of the week between Friday and Sunday. No later than the 2nd century, the Romans named Saturday ("Saturn's Day") for the planet Saturn, which controlled the first hour of that day, according to Vettius Valens. The da ...
,
U.S. Independence Day and
Halloween are on Sunday,
Labor Day is on
September 6,
Thanksgiving
Thanksgiving is a national holiday celebrated on various dates in the United States, Canada, Grenada, Saint Lucia, Liberia, and unofficially in countries like Brazil and Philippines. It is also observed in the Netherlander town of Leiden ...
is on
November 25
Events Pre-1600
*571 BC – Servius Tullius, king of Rome, celebrates the first of his three triumphs for his victory over the Etruscans.
* 1034 – Máel Coluim mac Cináeda, King of Scots, dies. His grandson, Donnchad, son of Bethó ...
, and
Christmas
Christmas is an annual festival commemorating the birth of Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people around the world. A feast central to the Christian liturgical year ...
is on a
Saturday
Saturday is the day of the week between Friday and Sunday. No later than the 2nd century, the Romans named Saturday ("Saturn's Day") for the planet Saturn, which controlled the first hour of that day, according to Vettius Valens. The da ...
.
Calendars
This is the only year type where the ''n''th "
Doomsday" (this year Sunday) is not in ISO week ''n''; it is in ISO week ''n''-1.
Applicable years
Gregorian calendar
In the (currently used) Gregorian calendar, alongside
Sunday
Sunday is the day of the week between Saturday and Monday. In most Western countries, Sunday is a day of rest and a part of the weekend. It is often considered the first day of the week.
For most observant adherents of Christianity, Sund ...
,
Monday,
Wednesday or
Saturday
Saturday is the day of the week between Friday and Sunday. No later than the 2nd century, the Romans named Saturday ("Saturn's Day") for the planet Saturn, which controlled the first hour of that day, according to Vettius Valens. The da ...
, 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 Friday. The 28-year sub-cycle only spans across century years divisible by 400, e.g. 1600, 2000, and 2400.
400 year cycle:
*century 1: 010, 021, 027, 038, 049, 055, 066, 077, 083, 094, 100
*century 2: 106, 117, 123, 134, 145, 151, 162, 173, 179, 190
*century 3: 202, 213, 219, 230, 241, 247, 258, 269, 275, 286, 297
*century 4: 309, 315, 326, 337, 343, 354, 365, 371, 382, 393, 399
Julian calendar
In the now-obsolete Julian calendar, the fourteen types of year (seven common, seven leap) repeat in a
28-year cycle (1461 weeks). This sequence occurs exactly 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 4, 15 and 26 of the cycle are common years beginning on Friday. 2017 is year 10 of the cycle. Approximately 10.71% of all years are common years beginning on Friday.
References
{{DEFAULTSORT:Common Year Starting On Friday
Gregorian calendar
Julian calendar
Friday