Leap year starting on Wednesday

A leap year starting on Wednesday is any year with 366 days (i.e. it includes 29 February) that begins on Wednesday 1 January and ends on Thursday 31 December. Its dominical letters hence are ED. The most recent year of such kind was 2020 and the next one will be 2048 in the Gregorian calendar, or likewise, 2004 and 2032 in the obsolete Julian calendar, see below for more.^[1]

Any leap year that starts on Monday, Wednesday or Thursday has two Friday the 13ths: those two in this leap year occur in March and November. Common years starting on Thursday share this characteristic, but also have another in February.

This is the only leap year with three occurrences of Friday the 17th: those three in this leap year occur three months (13 weeks) apart: in January, April, and July. Common years starting on Sunday share this characteristic, in the months of February, March, and November.

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 Tuesday the 13th. Common years starting on Saturday share this characteristic, from July of the year that precedes it to September in that type of year.

Calendars

Calendar for any leap year starting on Wednesday,
presented as common in many English-speaking areas

ISO 8601-conformant calendar with week numbers for
any leap year starting on Wednesday (dominical letter ED)

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	January
01			01	02	03	04	05
02	06	07	08	09	10	11	12
03	13	14	15	16	17	18	19
04	20	21	22	23	24	25	26
05	27	28	29	30	31

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	February
05						01	02
06	03	04	05	06	07	08	09
07	10	11	12	13	14	15	16
08	17	18	19	20	21	22	23
09	24	25	26	27	28	29

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	March
09							01
10	02	03	04	05	06	07	08
11	09	10	11	12	13	14	15
12	16	17	18	19	20	21	22
13	23	24	25	26	27	28	29
14	30	31

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	April
14			01	02	03	04	05
15	06	07	08	09	10	11	12
16	13	14	15	16	17	18	19
17	20	21	22	23	24	25	26
18	27	28	29	30

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	May
18					01	02	03
19	04	05	06	07	08	09	10
20	11	12	13	14	15	16	17
21	18	19	20	21	22	23	24
22	25	26	27	28	29	30	31

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	June
23	01	02	03	04	05	06	07
24	08	09	10	11	12	13	14
25	15	16	17	18	19	20	21
26	22	23	24	25	26	27	28
27	29	30

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	July
27			01	02	03	04	05
28	06	07	08	09	10	11	12
29	13	14	15	16	17	18	19
30	20	21	22	23	24	25	26
31	27	28	29	30	31

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	August
31						01	02
32	03	04	05	06	07	08	09
33	10	11	12	13	14	15	16
34	17	18	19	20	21	22	23
35	24	25	26	27	28	29	30
36	31

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	September
36		01	02	03	04	05	06
37	07	08	09	10	11	12	13
38	14	15	16	17	18	19	20
39	21	22	23	24	25	26	27
40	28	29	30

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	October
40				01	02	03	04
41	05	06	07	08	09	10	11
42	12	13	14	15	16	17	18
43	19	20	21	22	23	24	25
44	26	27	28	29	30	31

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	November
44							01
45	02	03	04	05	06	07	08
46	09	10	11	12	13	14	15
47	16	17	18	19	20	21	22
48	23	24	25	26	27	28	29
49	30

Wk	Mo	Tu	We	Th	Fr	Sa	Su
	December
49		01	02	03	04	05	06
50	07	08	09	10	11	12	13
51	14	15	16	17	18	19	20
52	21	22	23	24	25	26	27
53	28	29	30	31

Applicable years

Gregorian Calendar

Leap years that begin on Wednesday, along with those starting on Tuesday, occur at a rate of approximately 14.43% (14 out of 97) of all total leap years in a 400-year cycle of the Gregorian calendar. Thus, their overall occurrence is 3.5% (14 out of 400).

For this kind of year, the corresponding ISO year has 53 weeks.

Gregorian leap years starting on Wednesday^[1]
Decade	1st	2nd	3rd	4th	5th	7th	8th	10th
17th century			1620		1648		1676
18th century		1716			1744		1772
19th century		1812		1840		1868		1896
20th century	1908			1936		1964		1992
21st century			2020		2048		2076
22nd century		2116			2144		2172
23rd century		2212		2240		2268		2296
24th century	2308			2336		2364		2392
25th century			2420		2448		2476
26th century		2516			2544		2572
27th century		2612		2640		2668		2696

400 year cycle

century 1: 20, 48, 76

century 2: 116, 144, 172

century 3: 212, 240, 268, 296

century 4: 308, 336, 364, 392

Julian Calendar

Like all leap year types, the one starting with 1 January on a Wednesday 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).

Julian leap years starting on Wednesday
Decade	1st	2nd	3rd	4th	5th	6th	7th	8th	9th	10th
15th century		1416			1444			1472		1500
16th century			1528			1556			1584
17th century		1612		1640			1668			1696
18th century			1724			1752		1780
19th century	1808			1836			1864			1892
20th century		1920			1948			1976
21st century	2004			2032		2060			2088
22nd century		2116			2144			2172		2200

Holidays

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. This is the only leap year when Victoria Day and Labour Day are 34 days apart. They are 27 days apart in all other leap years.
- Canada Day falls on a Wednesday
- Labour Day falls on its latest possible date, September 7 – this is the only leap year when Victoria Day and Labour Day are sixteen weeks apart (they are fifteen weeks apart in all other leap years)
- Thanksgiving Day falls on October 12
- Daylight saving ends on its earliest possible date, November 1 -This is the only leap year when Labour Day and the end of Daylight Saving Time are 55 days apart. They are 62 days apart in all other leap years

United States

- Martin Luther King Jr. Day falls on January 20
- President's Day falls on February 17
- 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. This is the only leap year when Memorial Day and Father’s Day are 27 days apart. They are 20 days apart in all other leap years. This is also the only leap year when the start of Daylight Saving Time and Father’s Day are 15 weeks apart. They are 14 weeks apart in all other leap years
- Independence Day falls on a Saturday
- Labor Day falls on its latest possible date, September 7 – this is the only leap year when Memorial Day and Labor Day are fifteen weeks apart (they are fourteen weeks apart in all other leap years). This is the only leap year when the start of Daylight Saving Time and Labor Day are 183 days apart. They are 176 days apart in all other leap years.
- Grandparents' Day falls on its latest possible date, September 13. This is the only leap year when Memorial Day and Grandparent’s Day are 111 days apart. They are 104 days apart in all other leap years. This is also the only leap year when the start of Daylight Saving Time and Grandparent’s Day are 27 weeks apart. They are 26 weeks apart in all other leap years
- Columbus Day falls on October 12
- Daylight saving ends on its earliest possible date, November 1. This is the only leap year when Labor Day and the end of Daylight Saving Time are 55 days apart. They are 62 days apart in all other leap years. This is also the only leap year when Father’s Day and the end of Daylight Saving Time are 19 weeks apart. They are 20 weeks apart in all other leap years. This is also the only leap year when Grandparent’s Day and the end of Daylight Saving Time are 7 weeks apart. They are 8 weeks apart in all other leap years
- Election Day falls on November 3
- Thanksgiving Day falls on November 26

References

↑ ^1.0 ^1.1 Robert van Gent (2017). "The Mathematics of the ISO 8601 Calendar". Utrecht University, Department of Mathematics. Retrieved 20 July 2017.

[math-1] 1.0 ^1.1 Robert van Gent (2017). "The Mathematics of the ISO 8601 Calendar". Utrecht University, Department of Mathematics. Retrieved 20 July 2017.

[1]

Calendars

Applicable years

Gregorian Calendar

Julian Calendar

Holidays

International

Roman Catholic Solemnities

Australia and New Zealand

British Isles

Canada

United States

References