Leap week calendar - Citizendia

A leap week calendar is a calendar system with a whole number of weeks every year, and with every year starting on the same weekday. The word Calendar consist of two words 1 Cal ( in Pashto means Year in Hindi and Persian is Sal- also means Year Most leap week calendars are proposed reforms to the civil calendar, but some - such as the ISO week number calendar - are simply conveniences for specific purposes. A calendar reform is any significant revision of a Calendar system The ISO week date system is a Leap week calendar system that is part of the ISO 8601 date and time standard

The ISO calendar in question is a variation of the Gregorian calendar that is used (mainly) in government and business for fiscal years, as well as in timekeeping. The Gregorian calendar is the most widely used Calendar in the world today For the government of parliamentary systems see Executive (government. A business (also called firm or an enterprise) is a legally recognized organizational entity designed to provide goods and/or services to A fiscal year (or financial year, or sometimes budget year) is a period used for calculating annual ("yearly" Financial statements in Businesses In this system a year (ISO year) has 52 or 53 full weeks (364 or 371 days).

Leap week calendars vary on whether the concept of month is preserved and whether the month (if preserved) has a whole number of weeks.

Most leap week calendars take advantage of the fact that 400 Gregorian Calendar years have exactly 20,871 weeks, so with non-leap years of 52 weeks, this means there are 71 leap weeks every 400 years. The Gregorian calendar is the most widely used Calendar in the world today These include the Pax Calendar, CCC&T as well as the ISO week dates. The Pax calendar was invented by James A Colligan in 1930 as a reform of the Gregorian calendar. The Common-Civil-Calendar-and-Time Calendar (C&T is a proposal for Calendar reform. The ISO week date system is a Leap week calendar system that is part of the ISO 8601 date and time standard

1 Advantages
2 Disadvantages
3 Year structures
4 External links

Advantages

There are no variations between day of week between years for a specific date.
The calendar starts on the same day and week every year.
Unlike the regular calendar, variations of years are limited to a possible addition of a leap week.
There are no fragments of weeks at the end of the year.
Unlike certain proposed calendar reforms such as the World Calendar and International Fixed Calendar, there is no need to modify the week. The World Calendar is a proposed reform of the Gregorian calendar created by Elisabeth Achelis of Brooklyn New York in 1930 The International Fixed Calendar (also known as the International Perpetual calendar, the Cotsworth plan, the Eastman plan, the 13 Month This avoids opposition from religious groups who object to interruption of the seven-weekday sequence.

Disadvantages

A year with a leap week is at least 7 days longer than a year without a leap week, consequently the equinoxes and solstices must vary over 7 days, (i. e. ±3 of the average date), or even more, such as 19 days in the Pax Calendar. The Pax calendar was invented by James A Colligan in 1930 as a reform of the Gregorian calendar.

Year structures

Calendars with leap week at the end
ISO week	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		32	33	34	35		36	37	38	39	40	41	42	43	44			45	46	47	48		49	50	51	52	53
Day
13 months	1				2						3							4					5							6						7						8					9					10				11						12					13				*
Bonavian	1							2						3						4							5							6					7							8					9				10							11					12				*
Sym454	1				2									3						4				5										6					7					8							9				10				11								12				*
30-31-30	1					2							3							4						5							6						7						8					9					10					11						12					*
Gregorian	January						February					March							April						May							June						July							August					September					October						November					December					*
Quarter	1														2													3													4

Note that the new years of the calendars shown need not be synchonised. A calendar reform is any significant revision of a Calendar system The Symmetry454 Calendar (Sym454 is a proposal for Gregorian Calendar reform.

External links

Leap Week Calendars
List of ISO leap years - here the leap weeks are called Newton

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Contents

Advantages

Disadvantages

Year structures

External links