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Leap year starting on Thursday

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A leap year starting on Thursday is any year with 366 days (i.e. it includes 29 February) that begins on Thursday, 1 January, and ends on Friday, 31 December. Its dominical letter hence is DC, such as the years 1948, 1976, 2004, 2032, 2060 in the Gregorian calendar[1] or, likewise, 1988 and 2016 in the obsolete Julian calendar.

Calendars

Calendar for any leap year starting on Thursday,
presented as common in many English-speaking areas
January
Su Mo Tu We Th Fr Sa
01 02 03
04 05 06 07 08 09 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31
 
February
Su Mo Tu We Th Fr Sa
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29  
 
March
Su Mo Tu We Th Fr Sa
01 02 03 04 05 06
07 08 09 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30 31  
 
April
Su Mo Tu We Th Fr Sa
01 02 03
04 05 06 07 08 09 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30
 
May
Su Mo Tu We Th Fr Sa
01
02 03 04 05 06 07 08
09 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31  
June
Su Mo Tu We Th Fr Sa
01 02 03 04 05
06 07 08 09 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30  
 
July
Su Mo Tu We Th Fr Sa
01 02 03
04 05 06 07 08 09 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31
 
August
Su Mo Tu We Th Fr Sa
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31  
 
September
Su Mo Tu We Th Fr Sa
01 02 03 04
05 06 07 08 09 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30  
 
October
Su Mo Tu We Th Fr Sa
01 02
03 04 05 06 07 08 09
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31  
November
Su Mo Tu We Th Fr Sa
01 02 03 04 05 06
07 08 09 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30  
 
December
Su Mo Tu We Th Fr Sa
01 02 03 04
05 06 07 08 09 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31  
 
ISO 8601-conformant calendar with week numbers for
any leap year starting on Thursday (dominical letter DC)
January
Wk Mo Tu We Th Fr Sa Su
01 01 02 03 04
02 05 06 07 08 09 10 11
03 12 13 14 15 16 17 18
04 19 20 21 22 23 24 25
05 26 27 28 29 30 31  
   
February
Wk Mo Tu We Th Fr Sa Su
05 01
06 02 03 04 05 06 07 08
07 09 10 11 12 13 14 15
08 16 17 18 19 20 21 22
09 23 24 25 26 27 28 29
   
March
Wk Mo Tu We Th Fr Sa Su
10 01 02 03 04 05 06 07
11 08 09 10 11 12 13 14
12 15 16 17 18 19 20 21
13 22 23 24 25 26 27 28
14 29 30 31  
   
April
Wk Mo Tu We Th Fr Sa Su
14 01 02 03 04
15 05 06 07 08 09 10 11
16 12 13 14 15 16 17 18
17 19 20 21 22 23 24 25
18 26 27 28 29 30  
   
May
Wk Mo Tu We Th Fr Sa Su
18 01 02
19 03 04 05 06 07 08 09
20 10 11 12 13 14 15 16
21 17 18 19 20 21 22 23
22 24 25 26 27 28 29 30
23 31  
June
Wk Mo Tu We Th Fr Sa Su
23 01 02 03 04 05 06
24 07 08 09 10 11 12 13
25 14 15 16 17 18 19 20
26 21 22 23 24 25 26 27
27 28 29 30  
   
July
Wk Mo Tu We Th Fr Sa Su
27 01 02 03 04
28 05 06 07 08 09 10 11
29 12 13 14 15 16 17 18
30 19 20 21 22 23 24 25
31 26 27 28 29 30 31  
   
August
Wk Mo Tu We Th Fr Sa Su
31 01
32 02 03 04 05 06 07 08
33 09 10 11 12 13 14 15
34 16 17 18 19 20 21 22
35 23 24 25 26 27 28 29
36 30 31  
September
Wk Mo Tu We Th Fr Sa Su
36 01 02 03 04 05
37 06 07 08 09 10 11 12
38 13 14 15 16 17 18 19
39 20 21 22 23 24 25 26
40 27 28 29 30  
   
October
Wk Mo Tu We Th Fr Sa Su
40 01 02 03
41 04 05 06 07 08 09 10
42 11 12 13 14 15 16 17
43 18 19 20 21 22 23 24
44 25 26 27 28 29 30 31
   
November
Wk Mo Tu We Th Fr Sa Su
45 01 02 03 04 05 06 07
46 08 09 10 11 12 13 14
47 15 16 17 18 19 20 21
48 22 23 24 25 26 27 28
49 29 30  
   
December
Wk Mo Tu We Th Fr Sa Su
49 01 02 03 04 05
50 06 07 08 09 10 11 12
51 13 14 15 16 17 18 19
52 20 21 22 23 24 25 26
53 27 28 29 30 31  
   

Applicable years

Gregorian Calendar

The 15 types of years repeat in a 400-year cycle (20871 weeks) in the Gregorian calendar. 43 common years per cycle or exactly 3.25 % start on a Thursday. For this kind of year, the corresponding ISO year has 53 weeks, and the ISO week 10 (which begins March 1) and all subsequent ISO weeks occur earlier than in all other years. That means, moveable holidays may occur one calendar week later than otherwise possible, e.g. Gregorian Easter Sunday in week 17 about once per leap cycle.

Gregorian leap years starting on Thursday[1]
Decade 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th
17th century 1604 1632 1660 1688
18th century 1728 1756 1784
19th century 1824 1852 1880
20th century 1920 1948 1976
21st century 2004 2032 2060 2088

Julian Calendar

Like all leap year types, the one starting with 1 January on a Thursday occurs exactly once in a 28-year cycle in the Julian calendar, i.e. in 3.57 percent of years.

Template:Julian solar cycle

The final two digits of Julian years repeat after 700 years, i.e. 25 cycles.

Julian leap years starting on Thursday
Decade 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th
15th century 1428 1456 1484
16th century 1512 1540 1568 1596
17th century 1624 1652 1680
18th century 1708 1736 1764 1792
19th century 1820 1848 1876
20th century 1904 1932 1960 1988
21st century 2016 2044 2072 2100
22nd century 2128 2156 2184

References

  1. ^ a b Robert van Gent (2005). "The Mathematics of the ISO 8601 Calendar". Utrecht University, Department of Mathematics.