Editing Common year starting on Thursday

{{Short description|none}}
A '''common year starting on Thursday''' is any non-[[leap year]] (i.e. a year with 365 days) that begins on [[Thursday]], [[1 January]], and ends on [[Thursday]], [[31 December]]. Its [[dominical letter]] hence is '''D'''. The most recent year of such kind was [[2015]], and the next one will be [[2026]] 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, [[2021]] and [[2027]] in the obsolete [[Julian calendar]], see [[#Applicable years|below for more]].

This is the only common year with three occurrences of [[Friday the 13th]]: those three in this common year [[February 13|occur in February]], [[March 13|March]], and [[November 13|November]]. [[Leap year starting on Sunday|Leap years starting on Sunday]] share this characteristic, for the months January, April and July. From February until March in this type of year is also the shortest period (one month) that runs between two instances of [[Friday the 13th]]. Additionally, this is the one of only two types of years overall where a [[Perfect month|rectangular February]] is possible, in places where Sunday is considered to be the first day of the week. [[Common years starting on Friday]] share this characteristic, when Monday is considered to be the first day of the week.

This year has four months (February, March, August and November) which begin on a weekend-day.

== Calendars ==
<!-- To avoid arbitrary years, use the most recent year of this type. 2015 was the most recent year of this type. -->
{{calendar|year=2015|show_year=off|title=Calendar for any [[common year]] starting on Thursday,<br />presented as common in many English-speaking areas}}

{{calendar|year=2015|show_year=off|format=iso|row=3|zero=0|title=[[ISO 8601]]-conformant calendar with [[ISO week date|week numbers]] for<br />any common year starting on Thursday (dominical letter D)}}

== Applicable years ==
=== Gregorian Calendar ===
In the (currently used) Gregorian calendar, alongside [[Common year starting on Tuesday|Tuesday]], the fourteen types of year (seven common, seven leap) repeat in a 400-year cycle (20871 weeks). Forty-four common years per cycle or exactly 11% start on a Thursday. The 28-year sub-cycle only spans across century years divisible by 400, e.g. 1600, 2000, and 2400.

For this kind of year, the corresponding ISO year has 53 weeks, and the ISO week 10 (which begins March 2) and all subsequent ISO weeks occur earlier than in all other common years.

{| class="wikitable"
|+ Gregorian common years starting on Thursday<ref name="math"/>
!scope=row| Decade
!colspan=2| 1st !! 2nd !! 3rd !!colspan=2| 4th !! 5th !!colspan=2| 6th !!colspan=2| 7th !! 8th !!colspan=2| 9th !!colspan=2| 10th
|- style="opacity: 0.5;"
! style="background-color:#efefef;" | [[16th century]]
|colspan=13| ''prior to first adoption (proleptic)'' || [[1587]] ||colspan=2| [[1598]]
|- style="opacity: 0.5;"
! style="background-color:#efefef;" | [[17th century]]
|colspan=2| [[1609]] || [[1615]] || [[1626]] ||colspan=2| [[1637]] || [[1643]] ||colspan=2| [[1654]] ||colspan=2| [[1665]] || [[1671]] ||colspan=2| [[1682]] || [[1693]] || [[1699]]
|-
! style="background-color:#efefef;" | [[18th century]]
|colspan=2| [[1705]] || [[1711]] || [[1722]] || [[1733]] || [[1739]] || [[1750]] ||colspan=2| — || [[1761]] || [[1767]] || [[1778]] ||colspan=2| [[1789]] ||colspan=2| [[1795]]
|-
! style="background-color:#efefef;" | [[19th century]]
| [[1801]] || [[1807]] || [[1818]] || [[1829]] ||colspan=2| [[1835]] || [[1846]] ||colspan=2| [[1857]] ||colspan=2| [[1863]] || [[1874]] ||colspan=2| [[1885]] ||colspan=2| [[1891]]
|-
! style="background-color:#efefef;" | [[20th century]]
|colspan=2| [[1903]] || [[1914]] || [[1925]] ||colspan=2| [[1931]] || [[1942]] || [[1953]] || [[1959]] ||colspan=2| — || [[1970]] || [[1981]] || [[1987]] ||colspan=2| [[1998]]
|-
! style="background-color:#efefef;" | [[21st century]]
|colspan=2| [[2009]] || [[2015]] || [[2026]] ||colspan=2| [[2037]] || [[2043]] ||colspan=2| [[2054]] ||colspan=2| [[2065]] || [[2071]] ||colspan=2| [[2082]] || [[2093]] || [[2099]]
|-
! style="background-color:#efefef;" | [[22nd century]]
|colspan=2| [[2105]] || [[2111]] || [[2122]] || [[2133]] || [[2139]] || [[2150]] ||colspan=2| — || [[2161]] || [[2167]] || [[2178]] ||colspan=2| [[2189]] ||colspan=2| [[2195]]
|-
! style="background-color:#efefef;" | [[23rd century]]
 | [[2201]] || [[2207]] || [[2218]] || [[2229]] ||colspan=2| [[2235 (year)|2235]] || [[2246]] ||colspan=2| [[2257]] ||colspan=2| [[2263]] || [[2274]] ||colspan=2| [[2285]] ||colspan=2| [[2291]]
|-
! style="background-color:#efefef;" | [[24th century]]
 |colspan=2| [[2303]] || [[2314]] || [[2325]] ||colspan=2| [[2331]] || [[2342]] || [[2353]] || [[2359]] ||colspan=2| — || [[2370]] || [[2381]] || [[2387]] ||colspan=2| [[2398]]
|-
! style="background-color:#efefef;" | [[25th century]]
|colspan=2| [[2409]] || [[2415]] || [[2426]] ||colspan=2| [[2437]] || [[2443]] ||colspan=2| [[2454]] ||colspan=2| [[2465]] || [[2471]] ||colspan=2| [[2482]] || [[2493]] || [[2499]]
|}

{| class="wikitable"
|+ 400-year cycle
|-
! 0–99
| 9 || 15 || 26 || 37 || 43 || 54 || 65 || 71 || 82 || 93 || 99
|-
! 100–199
| 105 || 111 || 122 || 133 || 139 || 150 || 161 || 167 || 178 || 189 || 195
|-
! 200–299
| 201 || 207 || 218 || 229 || 235 || 246 || 257 || 263 || 274 || 285 || 291
|-
! 300–399
| 303 || 314 || 325 || 331 || 342 || 353 || 359 || 370 || 381 || 387 || 398
|}

=== Julian Calendar ===
In the now-obsolete Julian calendar, the fourteen types of year (seven common, seven leap) repeat in a [[solar cycle (calendar)|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, as 29 February has no letter). 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 3, 14 and 20 of the cycle are common years beginning on Thursday. 2017 is year 10 of the cycle. Approximately 10.71% of all years are common years beginning on Thursday.

{| class="wikitable"
|+ Julian common years starting on Thursday
!scope=row| Decade
!colspan=2| 1st !!colspan=2| 2nd !!colspan=2| 3rd !!colspan=2| 4th !!colspan=2| 5th !!colspan=2| 6th !!colspan=2| 7th !!colspan=2| 8th !!colspan=2| 9th !!colspan=2| 10th
|-
! style="background-color:#efefef;" | 15th century
|colspan=2| [[1405]] ||colspan=2| [[1411]] ||colspan=2| [[1422]] || [[1433]] ||colspan=2| [[1439]] ||colspan=2| [[1450]] ||colspan=2| — || [[1461]] ||colspan=2| [[1467]] ||colspan=2| [[1478]] || [[1489]] ||colspan=2| [[1495]]
|-
! style="background-color:#efefef;" | 16th century
|colspan=2| [[1506]] ||colspan=2| [[1517]] ||colspan=2| [[1523]] ||colspan=2| [[1534]] ||colspan=2| [[1545]] ||colspan=2| [[1551]] ||colspan=2| [[1562]] || [[1573]] ||colspan=2| [[1579]] <!-- Wikipedia year articles refer to Gregorian years from 1582 --> ||colspan=2| 1590 ||colspan=2| —
|-
! style="background-color:#efefef;" | 17th century
| 1601 ||colspan=2| 1607 ||colspan=2| 1618 ||colspan=2| 1629 || 1635 ||colspan=2| 1646 ||colspan=2| 1657 ||colspan=2| 1663 || colspan="2" | 1674 ||colspan=2| 1685 ||colspan=2| 1691
|-
! style="background-color:#efefef;" | 18th century
|colspan=2| 1702 || 1713 ||colspan=2| 1719 ||colspan=2| 1730 ||colspan=2| — || 1741 || 1747 ||colspan=2| 1758 ||colspan=2| 1769 ||colspan=2| 1775 ||colspan=2| 1786 ||colspan=2| 1797
|-
! style="background-color:#efefef;" | 19th century
|colspan=2| 1803 ||colspan=2| 1814 ||colspan=2| 1825 ||colspan=2| 1831 ||colspan=2| 1842 || 1853 || 1859 ||colspan=2| 1870 ||colspan=2| — || 1881 ||1887 ||colspan=2| 1898
|-
! style="background-color:#efefef;" | 20th century
|colspan=2| 1909 ||colspan=2| 1915 ||colspan=2| 1926 ||colspan=2| 1937 ||colspan=2| 1943 ||colspan=2| 1954 ||colspan=2| 1965 ||colspan=2| 1971 ||colspan=2| 1982 || 1993 || 1999
|-
! style="background-color:#efefef;" | 21st century
|colspan=2| 2010 ||colspan=2| — || 2021 || 2027 ||colspan=2| 2038 ||colspan=2| 2049 ||colspan=2| 2055 ||colspan=2| 2066 ||colspan=2| 2077 ||colspan=2|2083 ||colspan=2| 2094
|}

== Holidays ==

=== International ===
* [[Valentine's Day]] falls on a [[Saturday]]
* [[Grandparents' Day|World Day for Grandparents and the Elderly]] falls on [[July 26]]
* [[Halloween]] falls on a [[Saturday]]
* [[Christmas Day]] falls on a [[Friday]]

=== Roman Catholic Solemnities ===
* [[Epiphany (holiday)|Epiphany]] falls on a [[Tuesday]]
* [[Candlemas]] falls on a [[Monday]]
* [[Saint Joseph's Day]] falls on a [[Thursday]]
* The [[Annunciation of Jesus]] falls on a [[Wednesday]]
* The [[Nativity of John the Baptist]] falls on a [[Wednesday]]
* The [[Solemnity of Saints Peter and Paul]] falls on a [[Monday]]
* The [[Transfiguration of Jesus]] falls on a [[Thursday]]
* The [[Assumption of Mary]] falls on a [[Saturday]]
* The [[Exaltation of the Holy Cross]] falls on a [[Monday]]
* [[All Saints' Day]] falls on a [[Sunday]]
* [[All Souls' Day]] falls on a [[Monday]]
* The [[Feast of Christ the King]] falls on [[November 22]] (or on its earliest possible date of [[October 25]] in versions of the calendar between 1925 and 1962)
* The [[First Sunday of Advent]] falls on [[November 29]]
* The [[Immaculate Conception]] falls on a [[Tuesday]]
* [[Gaudete Sunday]] falls on [[December 13]]
* [[Rorate Sunday]] falls on [[December 20]]

=== Australia and New Zealand ===
* [[Australia Day]] falls on a [[Monday]]
* [[Waitangi Day]] falls on a [[Friday]]
* [[Daylight saving]] ends on [[April 5]]
* [[ANZAC Day]] falls on a [[Saturday]]
* [[Mother's Day]] falls on [[May 10]]
* [[Father's Day]] falls on [[September 6]]
* Daylight saving begins on [[September 27]] in New Zealand and [[October 4]] in Australia

=== British Isles ===
* [[Saint David's Day]] falls on a [[Sunday]]
* [[Mother's Day]] falls on its earliest possible date of [[March 1]], or on [[March 8]], [[March 15]], [[March 22]] or [[March 29]]
* [[Saint Patrick's Day]] falls on a [[Tuesday]]
* [[Daylight saving]] begins on [[March 29]]
* [[Saint George's Day]] falls on a [[Thursday]]
* [[Father's Day]] falls on its latest possible date, [[June 21]]. This is only common year when Father's Day falls on ISO week 25. It falls on ISO week 24 in all of the common years.
* [[Orangeman's Day]] falls on a [[Sunday]]
* Daylight saving ends on its earliest possible date, [[October 25]]
* [[Guy Fawkes Night]] falls on a [[Thursday]]
* [[Saint Andrew's Day]] falls on a [[Monday]]

=== Canada ===
* [[Daylight saving]] begins on its earliest possible date, [[March 8]]
* [[Mother's Day]] falls on [[May 10]]
* [[Victoria Day]] falls on its earliest possible date, [[May 18]]
* [[Father's Day]] falls on its latest possible date, [[June 21]]
* [[Canada Day]] falls on a [[Wednesday]]
* [[Labour Day (Canada)|Labour Day]] falls on its latest possible date, [[September 7]] – this is the only common year when Victoria Day and Labour Day are sixteen weeks apart (they are fifteen weeks apart in all other common years)
* [[Thanksgiving Day (Canada)|Thanksgiving Day]] falls on [[October 12]]
* Daylight saving ends on its earliest possible date, [[November 1]]

=== United States ===
* [[Martin Luther King Jr. Day]] falls on [[January 19]]
* [[President's Day]] falls on [[February 16]]
* [[Daylight saving]] begins on its earliest possible date, [[March 8]]
* [[Mother's Day]] falls on [[May 10]]
* [[Memorial Day]] falls on its earliest possible date, [[May 25]]
* [[Juneteenth]] falls on a [[Friday]]
* [[Father's Day]] falls on its latest possible date, [[June 21]]
* [[Independence Day (United States)|Independence Day]] falls on a [[Saturday]]
* [[Labor Day (United States)|Labor Day]] falls on its latest possible date, [[September 7]] – this is the only common year when Memorial Day and Labor Day are fifteen weeks apart (they are fourteen weeks apart in all other common years)
* [[Grandparents' Day]] falls on its latest possible date, [[September 13]]
* [[Columbus Day]] falls on [[October 12]]
* Daylight saving ends on its earliest possible date, [[November 1]]
* [[Thanksgiving Day]] falls on [[November 26]]

== References ==
{{Reflist}}
{{List of calendars}}

{{DEFAULTSORT:Common Year Starting On Thursday}}
[[Category:Gregorian calendar]]
[[Category:Julian calendar]]
[[Category:Thursday]]