Leap year starting on Saturday

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.

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 is the only type of Leap Year that starts and ends on weekends.

Calendars

Calendar for any leap year starting on Saturday,
presented as common in many English-speaking areas
January
SuMoTuWeThFrSa
1
2345678
9101112131415
16171819202122
23242526272829
3031 
February
SuMoTuWeThFrSa
12345
6789101112
13141516171819
20212223242526
272829 
 
March
SuMoTuWeThFrSa
1234
567891011
12131415161718
19202122232425
262728293031 
 
April
SuMoTuWeThFrSa
1
2345678
9101112131415
16171819202122
23242526272829
30 
May
SuMoTuWeThFrSa
123456
78910111213
14151617181920
21222324252627
28293031 
 
June
SuMoTuWeThFrSa
123
45678910
11121314151617
18192021222324
252627282930
 
July
SuMoTuWeThFrSa
1
2345678
9101112131415
16171819202122
23242526272829
3031 
August
SuMoTuWeThFrSa
12345
6789101112
13141516171819
20212223242526
2728293031 
 
September
SuMoTuWeThFrSa
12
3456789
10111213141516
17181920212223
24252627282930
 
October
SuMoTuWeThFrSa
1234567
891011121314
15161718192021
22232425262728
293031 
 
November
SuMoTuWeThFrSa
1234
567891011
12131415161718
19202122232425
2627282930 
 
December
SuMoTuWeThFrSa
12
3456789
10111213141516
17181920212223
24252627282930
31 
ISO 8601-conformant calendar with week numbers for
any leap year starting on Saturday (dominical letter BA)
January
WkMoTuWeThFrSaSu
520102
0103040506070809
0210111213141516
0317181920212223
0424252627282930
0531 
February
WkMoTuWeThFrSaSu
05010203040506
0607080910111213
0714151617181920
0821222324252627
092829 
  
March
WkMoTuWeThFrSaSu
090102030405
1006070809101112
1113141516171819
1220212223242526
132728293031 
  
April
WkMoTuWeThFrSaSu
130102
1403040506070809
1510111213141516
1617181920212223
1724252627282930
  
May
WkMoTuWeThFrSaSu
1801020304050607
1908091011121314
2015161718192021
2122232425262728
22293031 
  
June
WkMoTuWeThFrSaSu
2201020304
2305060708091011
2412131415161718
2519202122232425
262627282930 
  
July
WkMoTuWeThFrSaSu
260102
2703040506070809
2810111213141516
2917181920212223
3024252627282930
3131 
August
WkMoTuWeThFrSaSu
31010203040506
3207080910111213
3314151617181920
3421222324252627
3528293031 
  
September
WkMoTuWeThFrSaSu
35010203
3604050607080910
3711121314151617
3818192021222324
39252627282930
  
October
WkMoTuWeThFrSaSu
3901
4002030405060708
4109101112131415
4216171819202122
4323242526272829
443031 
November
WkMoTuWeThFrSaSu
440102030405
4506070809101112
4613141516171819
4720212223242526
4827282930 
  
December
WkMoTuWeThFrSaSu
48010203
4904050607080910
5011121314151617
5118192021222324
5225262728293031
  

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).

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).

Holidays

International

Roman Catholic Solemnities

Australia and New Zealand

British Isles

Canada

United States

References

Uses material from the Wikipedia article Leap year starting on Saturday, released under the CC BY-SA 4.0 license.