Common year starting on Thursday

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[1] or, likewise, 2021 and 2027 in the obsolete Julian calendar, see below for more.

This is the only common year with three occurrences of Friday the 13th: those three in this common year occur in February, March, and November. 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 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, but only in places where Monday is considered to be the first day of the week.

Calendars

Calendar for any common year starting on Thursday,
presented as common in many English-speaking areas
January
SuMoTuWeThFrSa
010203
04050607080910
11121314151617
18192021222324
25262728293031
 
February
SuMoTuWeThFrSa
01020304050607
08091011121314
15161718192021
22232425262728
 
 
March
SuMoTuWeThFrSa
01020304050607
08091011121314
15161718192021
22232425262728
293031 
 
April
SuMoTuWeThFrSa
01020304
05060708091011
12131415161718
19202122232425
2627282930 
 
May
SuMoTuWeThFrSa
0102
03040506070809
10111213141516
17181920212223
24252627282930
31 
June
SuMoTuWeThFrSa
010203040506
07080910111213
14151617181920
21222324252627
282930 
 
July
SuMoTuWeThFrSa
01020304
05060708091011
12131415161718
19202122232425
262728293031 
 
August
SuMoTuWeThFrSa
01
02030405060708
09101112131415
16171819202122
23242526272829
3031 
September
SuMoTuWeThFrSa
0102030405
06070809101112
13141516171819
20212223242526
27282930 
 
October
SuMoTuWeThFrSa
010203
04050607080910
11121314151617
18192021222324
25262728293031
 
November
SuMoTuWeThFrSa
01020304050607
08091011121314
15161718192021
22232425262728
2930 
 
December
SuMoTuWeThFrSa
0102030405
06070809101112
13141516171819
20212223242526
2728293031 
 
ISO 8601-conformant calendar with week numbers for
any common year starting on Thursday (dominical letter D)
January
WkMoTuWeThFrSaSu
0101020304
0205060708091011
0312131415161718
0419202122232425
05262728293031 
  
February
WkMoTuWeThFrSaSu
0501
0602030405060708
0709101112131415
0816171819202122
09232425262728
  
March
WkMoTuWeThFrSaSu
0901
1002030405060708
1109101112131415
1216171819202122
1323242526272829
143031 
April
WkMoTuWeThFrSaSu
140102030405
1506070809101112
1613141516171819
1720212223242526
1827282930 
  
May
WkMoTuWeThFrSaSu
18010203
1904050607080910
2011121314151617
2118192021222324
2225262728293031
  
June
WkMoTuWeThFrSaSu
2301020304050607
2408091011121314
2515161718192021
2622232425262728
272930 
  
July
WkMoTuWeThFrSaSu
270102030405
2806070809101112
2913141516171819
3020212223242526
312728293031 
  
August
WkMoTuWeThFrSaSu
310102
3203040506070809
3310111213141516
3417181920212223
3524252627282930
3631 
September
WkMoTuWeThFrSaSu
36010203040506
3707080910111213
3814151617181920
3921222324252627
40282930 
  
October
WkMoTuWeThFrSaSu
4001020304
4105060708091011
4212131415161718
4319202122232425
44262728293031 
  
November
WkMoTuWeThFrSaSu
4401
4502030405060708
4609101112131415
4716171819202122
4823242526272829
4930 
December
WkMoTuWeThFrSaSu
49010203040506
5007080910111213
5114151617181920
5221222324252627
5328293031 
  

Applicable years

Gregorian Calendar

In the (currently used) Gregorian calendar, alongside 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.

This type of year has 53 weeks in the week-day format of the ISO 8601 standard.

Gregorian common years starting on Thursday[1]
Decade1st2nd3rd4th5th6th7th8th9th10th
16th centuryprior to first adoption (proleptic)15871598
17th century16091615162616371643165416651671168216931699
18th century17051711172217331739175017611767177817891795
19th century18011807181818291835184618571863187418851891
20th century19031914192519311942195319591970198119871998
21st century20092015202620372043205420652071208220932099
22nd century21052111212221332139215021612167217821892195
23rd century22012207221822292235224622572263227422852291
24th century23032314232523312342235323592370238123872398
25th century24092415242624372443245424652471248224932499
400-year cycle
0–99915263743546571829399
100–199105111122133139150161167178189195
200–299201207218229235246257263274285291
300–399303314325331342353359370381387398

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). 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.

Julian common years starting on Thursday
Decade1st2nd3rd4th5th6th7th8th9th10th
15th century14051411142214331439145014611467147814891495
16th century1506151715231534154515511562157315791590
17th century16011607161816291635164616571683167416851691
18th century17021713171917301741174717581769177517861797
19th century18031814182518311842185318591870188118871898
20th century19091915192619371943195419651971198219931999
21st century2010202120272038204920552066207720832094

Holidays

International

Roman Catholic Solemnities

Australia and New Zealand

British Isles

Canada

United States

References