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ISO Week Date
The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization (ISO) since 1988 (last revised in 2019) and, before that, it was defined in ISO (R) 2015 since 1971. It is used (mainly) in government and business for fiscal years, as well as in timekeeping. This was previously known as "Industrial date coding". The system specifies a ''week year'' atop the Gregorian calendar by defining a notation for ordinal weeks of the year. The Gregorian leap cycle, which has 97 leap days spread across 400 years, contains a whole number of weeks (). In every cycle there are 71 years with an additional 53rd week (corresponding to the Gregorian years that contain 53 Thursdays). An average year is exactly 52.1775 weeks long; months ( year) average at exactly 4.348125 weeks/month. An ISO week-numbering year (also called ''ISO year'' informally) has 52 or 53 full weeks. That is 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISO 8601
ISO 8601 is an international standard covering the worldwide exchange and communication of date and time-related data. It is maintained by the International Organization for Standardization (ISO) and was first published in 1988, with updates in 1991, 2000, 2004, and 2019, and an amendment in 2022. The standard provides a well-defined, unambiguous method of representing calendar dates and times in worldwide communications, especially to avoid misinterpreting numeric dates and times when such data is transferred between countries with different conventions for writing numeric dates and times. ISO 8601 applies to these representations and formats: ''dates'', in the Gregorian calendar (including the proleptic Gregorian calendar); ''times'', based on the 24-hour timekeeping system, with optional UTC offset; '' time intervals''; and combinations thereof.ISO 8601:2004 section 1 Scope The standard does not assign specific meaning to any element of the dates/times represented: t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Any leap year that starts on Wednesday 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. Leap years starting on Sunday also share a similar characteristic to this type of leap year, three Friday the 13th's have a three month gap between them, the former two being in the common year preceding this type of leap year, those being September and December, and the latter being in this type of year, that being March. Leap years starting on Sunday share this by having January, April ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hanke–Henry Permanent Calendar
The Hanke–Henry Permanent Calendar (HHPC) is a proposal for calendar reform. It is one of many examples of leap week calendars, calendars that maintain synchronization with the solar year by intercalating entire weeks rather than single days. It is a modification of a previous proposal, Common-Civil-Calendar-and-Time (CCC&T). With the Hanke–Henry Permanent Calendar, every calendar date always falls on the same day of the week. A major feature of the calendar system is the abolition of time zones. Features While many calendar reforms aim to make the calendar more accurate, the Hanke–Henry Permanent Calendar focuses on making the calendar perennial, so that every date falls on the same day of the week, year after year. The familiar drift of weekdays concerning dates results from the fact that the number of days in a physical year (one full orbit of Earth around the Sun, approximately 365.24 days) is not a multiple of seven. By reducing common years to 364 days (52 weeks), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiscal Quarter
A fiscal year (also known as a financial year, or sometimes budget year) is used in government accounting, which varies between countries, and for budget purposes. It is also used for financial reporting by businesses and other organizations. Laws in many jurisdictions require company financial reports to be prepared and published on an annual basis but generally with the reporting period not aligning with the calendar year (1 January to 31 December). Taxation laws generally require accounting records to be maintained and taxes calculated on an annual basis, which usually corresponds to the fiscal year used for government purposes. The calculation of tax on an annual basis is especially relevant for direct taxes, such as income tax. Many annual government fees—such as council tax and license fees are also levied on a fiscal year basis, but others are charged on an anniversary basis. Some companies, such as Cisco Systems, end their fiscal year on the same day of the week each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cycle (calendar)
The solar cycle is a 28-year cycle of the Julian calendar, and 400-year cycle of the Gregorian calendar with respect to the week. It occurs because leap years occur every 4 years, typically observed by adding a day to the month of February, making it February 29th. There are 7 possible days to start a leap year, making a 28-year sequence. This cycle also occurs in the Gregorian calendar, but it is interrupted by years that are divisible by 100 but not by 400, which these are common years. This interruption has the effect of skipping 16 years of the solar cycle between February 28 and March 1. Because the Gregorian cycle of 400 years has exactly 146,097 days, i.e. exactly 20,871 weeks, one can say that the Gregorian so-called solar cycle lasts 400 years. Calendar years are usually marked by Dominical letters indicating the first Sunday in a new year, thus the term solar cycle can also refer to a repeating sequence of Dominical letters. Unless a year is not a leap year due to Greg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Any leap year that starts on Wednesday 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. Leap years starting on Sunday also share a similar characteristic to this type of leap year, three Friday the 13th's have a three month gap between them, the former two being in the common year preceding this type of leap year, those being September and December, and the latter being in this type of year, that being March. Leap years starting on Sunday share this by having January, April ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominical Letter
Dominical letters or Sunday letters are a method used to determine the day of the week for particular dates. When using this method, each year is assigned a letter (or pair of letters for leap years) depending on which day of the week the year starts with. The Dominical letter for the current year 2025 is E. Dominical letters are derived from the Roman practice of marking the repeating sequence of eight letters A–H (commencing with A on January 1) on stone calendars to indicate each day's position in the eight-day market week ('' nundinae''). The word is derived from the number nine due to their practice of inclusive counting. After the introduction of Christianity a similar sequence of seven letters A–G was added alongside, again commencing with January 1. The dominical letter marks the Sundays. Nowadays they are used primarily as part of the computus, which is the method of calculating the date of Easter. A common year is assigned a single dominical letter, indicating which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leap Year Starting On Sunday
A leap year starting on Sunday is any year with 366 days (i.e. it includes 29 February) that begins on Sunday, 1 January, and ends on Monday, 31 December. Its dominical letters hence are AG. The most recent year of such kind was 2012, and the next one will be 2040 in the Gregorian calendar or, likewise 2024 and 2052 in the obsolete Julian calendar. This is the only leap year with three occurrences of Friday the 13th: those three in this leap year occur three months (13 weeks) apart: January 13, in January, April 13, April, and July 13, July. Common year starting on Thursday, Common years starting on Thursday share this characteristic, in the months of February, March, and November. Additionally, 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 Monday is considered the first day of the week. This year has five months (January, April, July, September and December) which begin on a weekend-day. This i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Year Starting On Sunday
A common year starting on Sunday is any non-leap year (i.e. a year with 365 days) that begins on Sunday, January 1, 1 January, and ends on Sunday, December 31, 31 December. Its dominical letter hence is A. The most recent year of such kind was 2023, and the next one will be 2034 in the Gregorian calendar, or, likewise, 2018 and 2029 in the obsolete Julian calendar, see #Applicable years, below for more. Any common year that starts on a Sunday has two Friday the 13ths: those two in this common year January 13, occur in January and October 13, October. This year has four months (January, April, July and October) which begin on a weekend-day. Calendars Applicable years Gregorian Calendar In the (currently used) Gregorian calendar, alongside Common year starting on Monday, Monday, Common year starting on Wednesday, Wednesday, Common year starting on Friday, Friday or Common year starting on Saturday, Saturday, the fourteen types of year (seven common, seven leap) repeat in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Year Starting On Saturday
A common year starting on Saturday is any non-leap year (i.e. a year with 365 days) that begins on Saturday, 1 January, and ends on Saturday, 31 December. Its dominical letter hence is B. The most recent year of such kind was 2022, and the next one will be 2033 in the Gregorian calendar or, likewise, 2023 and 2034 in the obsolete Julian calendar. See below for more. Any common year that starts on Saturday has only one Friday the 13th: the only one in this common year occurs in May. Leap years starting on Friday share this characteristic. From July of the year that precedes this year until September in this type of year is the longest period (14 months) that occurs without a Tuesday the 13th. This year has three months (January, May and October) which begin on a weekend-day. Calendars Applicable years Gregorian Calendar In the (currently used) Gregorian calendar, alongside Sunday, Monday, Wednesday or Friday, the fourteen types of year (seven common, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leap Year Starting On Friday
A leap year starting on Friday is any year with 366 days (i.e. it includes 29 February) that begins on Friday 1 January and ends on Saturday 31 December. Its dominical letters hence are CB. The most recent year of such kind was 2016, and the next one will be 2044 in the Gregorian calendar or, likewise, 2000 and 2028 in the obsolete Julian calendar. Any leap year that starts on Friday has only one Friday the 13th: the only one in this leap year occurs in May. Common years starting on Saturday share this characteristic. This is also the only year in which February has five Mondays, as the leap day adds that extra Monday. This year has two months (May and October) which begin on a weekend-day. Since at least one month begins on each day of the week in all years, this is the fewest possible number of months to begin on a weekend-day in a given year; this also occurs in a common year starting on Friday, in which case the two months are May and August. Calendars Applic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
