Leap year starting on Monday

Template:Short description A leap year starting on Monday is any year with 366 days (i.e. it includes 29 February) that begins on Monday, 1 January, and ends on Tuesday, 31 December. Its dominical letters hence are GF. The most recent year of such kind was 2024, and the next one will be 2052 in the Gregorian calendar<ref name="math">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> or, likewise, 2008 and 2036 in the obsolete Julian calendar.

Any leap year that starts on Monday has two Friday the 13ths: those two in this leap year occur in September and December. Common years starting on Tuesday share this characteristic.

This year has three months (June, September and December) which begin on a weekend-day.

CalendarsEdit

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presented as common in many English-speaking areas
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any leap year starting on Monday (dominical letter GF)
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Applicable yearsEdit

Gregorian CalendarEdit

Leap years that begin on Monday, along with those starting on Saturday and Thursday, occur least frequently: 13 out of 97 (≈ 13.4%) total leap years in a 400-year cycle of the Gregorian calendar. Their overall frequency is thus 3.25% (13 out of 400) of years.

Gregorian leap years starting on Monday<ref name=math/>
Decade	1st	2nd	3rd	4th	5th	6th	7th	8th	10th
16th century	prior to first adoption (proleptic)								1596
17th century			1624			1652		1680
18th century		1720			1748			1776
19th century		1816			1844			1872
20th century		1912		1940			1968		1996
21st century			2024			2052		2080
22nd century		2120			2148			2176
23rd century		2216			2244			2272
24th century		2312		2340			2368		2396
25th century			2424			2452		2480
26th century		2520			2548			2576
27th century		2616			2644			2672

400-year cycle
0–99	24	52	80
100–199	120	148	176
200–299	216	244	272
300–399	312	340	368	396

Julian CalendarEdit

Like all leap year types, the one starting with 1 January on a Monday 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 Monday
Decade	1st	2nd	3rd	4th	5th	6th	7th	8th	9th	10th
14th century	1308			1336			1364			1392
15th century		1420			1448			1476
16th century	1504			1532		1560			1588
17th century		1616			1644			1672		1700
18th century			1728			1756			1784
19th century		1812		1840			1868			1896
20th century			1924			1952		1980
21st century	2008			2036			2064			2092
22nd century		2120			2148			2176

HolidaysEdit

InternationalEdit

Valentine's Day falls on a Wednesday
The leap day (February 29) falls on a Thursday
World Day for Grandparents and the Elderly falls on its latest possible date, July 28
Halloween falls on a Thursday
Christmas Day falls on a Wednesday

Roman Catholic SolemnitiesEdit

Epiphany falls on a Saturday or, in places when it is transferred to a Sunday, January 7
Candlemas falls on a Friday
Saint Joseph's Day falls on a Tuesday
The Annunciation of Jesus falls on a Monday
The Nativity of John the Baptist falls on a Monday
The Solemnity of Saints Peter and Paul falls on a Saturday
The Transfiguration of Jesus falls on a Tuesday
The Assumption of Mary falls on a Thursday
The Exaltation of the Holy Cross falls on a Saturday
All Saints' Day falls on a Friday
All Souls' Day falls on a Saturday
The Feast of Christ the King falls on November 24 (or on October 27 in versions of the calendar between 1925 and 1962)
The First Sunday of Advent falls on December 1
The Immaculate Conception falls on a Sunday, thus transferred to Monday, December 9.
Gaudete Sunday falls on December 15
Rorate Sunday falls on December 22

Australia and New ZealandEdit

Australia Day falls on a Friday
Waitangi Day falls on a Tuesday
Daylight saving ends on its latest possible date, April 7 – the period of daylight saving which ends on April 7 of a leap year starting on Monday is the only period ending in any year to last 27 weeks in Australia and 28 weeks in New Zealand; in all other instances, the period of daylight saving lasts only 26 weeks in Australia and 27 weeks in New Zealand
ANZAC Day falls on a Thursday
Mother's Day falls on May 12
Father's Day falls on its earliest possible date, September 1
Daylight saving begins on September 29 in New Zealand and October 6 in Australia

British IslesEdit

Saint David's Day falls on a Friday
Mother's Day falls on March 3, March 10, March 17, March 24 or March 31
Saint Patrick's Day falls on a Sunday
Daylight saving begins on its latest possible date, March 31
Saint George's Day falls on a Tuesday
Father's Day falls on June 16
Orangeman's Day falls on a Friday
Daylight saving ends on October 27
Guy Fawkes Night falls on a Tuesday
Saint Andrew's Day falls on a Saturday

CanadaEdit

Daylight saving begins on March 10
Mother's Day falls on May 12
Victoria Day falls on May 20
Father's Day falls on June 16
Canada Day falls on a Monday
Labour Day falls on September 2
Thanksgiving Day falls on its latest possible date, October 14
Daylight saving ends on November 3

United StatesEdit

Martin Luther King Jr. Day falls on its earliest possible date, January 15
President's Day falls on February 19
Daylight saving begins on March 10
Mother's Day falls on May 12
Memorial Day falls on May 27
Father's Day falls on June 16
Juneteenth falls on a Wednesday
Independence Day falls on a Thursday
Labor Day falls on September 2
Grandparents' Day falls on September 8
Columbus Day falls on its latest possible date, October 14 (this is the only year when Martin Luther King Jr. Day and Columbus Day are 39 weeks apart) They are 38 weeks apart in all other years
Daylight saving ends on November 3
Election Day falls on November 5
Thanksgiving Day falls on its latest possible date, November 28 (this is also the only year when Martin Luther King Jr. Day and Thanksgiving are 318 days apart) They are 311 days apart in all other years

ReferencesEdit

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1 Jan	Count	Ratio	31 Dec	DL	DD	Count	Ratio	31 Dec	DL	DD	Count	Ratio
Year starts			Common years					Leap years
Sun	58	14.50 %	Sun	A	Tue	43	10.75 %	Mon	AG	Wed	15	Template:03.75 %
Mon	56	14.00 %	Mon	G	Wed	43	10.75 %	Tue	GF	Thu	13	Template:03.25 %
Tue	58	14.50 %	Tue	F	Thu	44	11.00 %	Wed	FE	Fri	14	Template:03.50 %
Wed	57	14.25 %	Wed	E	Fri	43	10.75 %	Thu	ED	Sat	14	Template:03.50 %
Thu	57	14.25 %	Thu	D	Sat	44	11.00 %	Fri	DC	Sun	13	Template:03.25 %
Fri	58	14.50 %	Fri	C	Sun	43	10.75 %	Sat	CB	Mon	15	Template:03.75 %
Sat	56	14.00 %	Sat	B	Mon	43	10.75 %	Sun	BA	Tue	13	Template:03.25 %
∑	400	100.0 %				303	75.75 %				97	24.25 %

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