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Different conventions exist around the world for date and time representation, both written and spoken.
| | This article needs additional citations for verification .(November 2009) |
Different conventions exist around the world for date and time representation, both written and spoken.
Differences can exist in:
International standard ISO 8601 (Representation of dates and times) defines unambiguous written all-numeric big-endian formats for dates, such as 2022-12-31 for 31 December 2022, and time, such as 23:59:58 for 23 hours, 59 minutes, and 58 seconds.
These standard notations have been adopted by many countries as a national standard, e.g., BS EN 28601 in the UK and similarly in other EU countries, ANSI INCITS 30-1997 (R2008), and FIPS PUB 4–2 in the United States (FIPS PUB 4-2 withdrawn in United States). [1] They are, in particular, increasingly widely used in computer applications, since the most to least significant digit order provides a simple method to order and sort time readings.
The little-endian format (day, month, year; 1 June 2022) is the most popular format worldwide, followed by the big-endian format (year, month, day; 2006 June 1). Dates may be written partly in Roman numerals (i.e. the month)[ citation needed ] or written out partly or completely in words in the local language.
The 24-hour clock is the most commonly used method worldwide to physically represent the time of day. Some regions utilize 24-hour time notation in casual speech as well, such as regions that speak German, French, or Romanian, though this is less common overall; other countries that utilize the 24-hour clock for displaying time physically may use the 12-hour clock more often in verbal communication.[ citation needed ]
In most English-speaking regions, the 12-hour clock is the predominant form of representing the time of day physically, while the 24-hour clock is generally used for contexts where unambiguity and accurate timekeeping are important, such as for public transport schedules. These are only generalizations, however, as there is no consistent rule for using one over the other: in the UK, train timetables will typically use 24-hour time,[ citation needed ] but road signs indicating time restrictions (e.g. on bus lanes) typically use 12-hour time, e.g. "Monday–Friday 6.30–8.30pm".[ citation needed ] The BBC website uses the 24-hour clock for its TV and radio programme listings,[ citation needed ] while BBC promotions for upcoming programmes give their times according to the 12-hour clock. Punctuation and spacing styles differ, even within English-speaking countries (6:30 p.m., 6:30 pm, 6:30 PM, 6.30pm, etc.).[ citation needed ]
Most people who live in countries that use one of the clocks dominantly are still able to understand both systems without much confusion; the statements "three o'clock" and "15:00", for example, are easily recognized as synonyms. While speaking, it may also be common for both systems to be used.[ citation needed ] People may often pronounce time in 12-hour notation, even when reading a 24-hour display, or use both notations simultaneously. In the latter case, the exact point in time is often registered in 24-hour notation ("The train leaves at fourteen forty-five ..."), while the 12-hour notation is used in more ambiguous contexts ("... so I will be back tonight some time after five.").[ citation needed ] While most countries lack formal abbreviations to distinguish before and after noon, many people will commonly use informal designations, such as "in the morning" or "in the evening".
In certain languages such as Spanish, Portuguese, Dutch, and English the hour is divided into quarters and halves, spoken of relative to the closest hour. In Arabic, thirds of an hour are also used. (xx:20, xx:40)
In Czech quarters and halves always refer to the following hour, e.g. čtvrt na osm (quarter on eight) meaning 7:15, půl osmé (half of eight) meaning 7:30 and tři čtvrtě na osm (three-quarters on eight) meaning 7:45. This corresponds to the time between 7:00 and 8:00 being the eighth hour of the day (the first hour starting at midnight). Russian uses the same convention: четверть восьмого (quarter of the eighth hour), полвосьмого (half of eight), без четверти восемь (eight without a quarter) meaning 7:15, 7:30, 7:45 respectively.
In many Germanic languages, with the exception of English, the half-hour refers to the next hour (half to nine rather than half past eight). In colloquial language, this can cause confusion between English and German (and other Germanic languages). In conversational English as spoken in the UK, half past eight (for 8:30) is often reduced to half eight (whereas in the United States half past eight would always be used). But in German halb acht, Dutch half acht, and Swedish halv åtta, all invariably mean 7:30. For the quarters, e.g. 7:15 and 7:45, in German different dialects use Viertel nach sieben or viertel acht (literally "quarter past seven" or "quarter eight"), and Viertel vor acht or dreiviertel acht (literally "quarter to eight" or "three-quarters eight"). [2]
In many countries it is common in spoken language to refer to times in minutes or fractions of an hour relative to the following hour rather than the previous one for times after the 30 minute mark – eg 8:55 would be said as "five to nine", and 6:45 would be "quarter to seven".
In French, the quarters are expressed as additions or subtractions of the full hour: sept heures et quart (literally "seven hours and quarter"), sept heures et demie ("seven hours and half"), huit heures moins le quart ("eight hours less the quarter"). It is also common to use this format in Portuguese, specifically in the northern part of Portugal.
In France and Vietnam, the common separator between hours and minutes is the letter "h" (18h45, for example). [3]
In Finland [4] and Indonesia, [5] the common separator between hours and minutes is a dot (18.45, for example).
A calendar date is a reference to a particular day represented within a calendar system. The calendar date allows the specific day to be identified. The number of days between two dates may be calculated. For example, "25 March 2024" is ten days after "15 March 2024". The date of a particular event depends on the observed time zone. For example, the air attack on Pearl Harbor that began at 7:48 a.m. Hawaiian time on 7 December 1941 took place at 3:18 a.m. Japan Standard Time, 8 December in Japan.
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. and p.m.. Each period consists of 12 hours numbered: 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11. The 12-hour clock has been developed since the second millennium BC and reached its modern form in the 16th century.
The modern 24-hour clock is the convention of timekeeping in which the day runs from midnight to midnight and is divided into 24 hours. This is indicated by the hours passed since midnight, from 00(:00) to 23(:59). This system, as opposed to the 12-hour clock, is the most commonly used time notation in the world today, and is used by the international standard ISO 8601.
The six-hour clock is a traditional timekeeping system used in the Thai and formerly the Lao language and the Khmer language, alongside the official 24-hour clock. Like other common systems, it counts twenty-four hours in a day, but divides the day into four quarters, counting six hours in each. The hours in each quarter are told with period-designating words or phrases, which are:
Date and time notation in the United States differs from that used in nearly all other countries. It is inherited from one historical branch of conventions from the United Kingdom. American styles of notation have also influenced customs of date notation in Canada, creating confusion in international commerce.
In Finland, the usual way of writing dates in normal text is with the months spelled out. The format varies according to the language used. In Finnish, a full stop is placed after the day to indicate an ordinal: 31. toukokuuta 2002; furthermore, the month is in the partitive case, always marked by -ta. The month can also be written first, now in genitive case : toukokuun 31. pnä 2002. In Swedish, the full stop is not used and the month is in nominative : den 31 maj 2002.
France most commonly records the date using the day-month-year format with an oblique stroke or slash as the separator with numerical values. The 24-hour clock is used to express time, using the letter h as the separator in between hours and minutes.
In Poland, the official system for representing dates and times follows the international ISO 8601 standard. However, in less official use, other conventions prevail, such as the day-month-year order and several Polish language abbreviations.
In Spain, date notation follows the DD/MM/YYYY format. Time notation depends on the level of formality and varies in written and spoken formats. Official time is given using the 24-hour clock, and the 12-hour clock is often used in informal speech.
Date and time notation in Sweden mostly follows the ISO 8601 standard: dates are generally written in the form YYYY-MM-DD. Although this format may be abbreviated in a number of ways, almost all Swedish date notations state the month between the year and the day. Months are not capitalised when written. The week number may also be used in writing and in speech. Times are generally written using 24-hour clock notation, with full stops as separators, although 12-hour clock notation is more frequently used in speech.
Date and time notation in the United Kingdom records the date using the day–month–year format. The ISO 8601 format (1999-12-31) is increasingly used for all-numeric dates. The time can be written using either the 24-hour clock (23:59) or the 12-hour clock (11:59 pm).
The European Committee for Standardization (CEN) and (CENELEC) adopted ISO 8601 with EN 28601, now EN ISO 8601. As a European Norm, CEN and CENELEC member states are obligated to adopt the standard as national standard without alterations as well.
In Turkey, the little endian date format is used, and 24-hour clock is more common than 12-hour clock system.
Date and time notation in Japan has historically followed the Japanese calendar and the nengō system of counting years. At the beginning of the Meiji period, Japan switched to the Gregorian calendar on Wednesday, 1 January 1873, but for much domestic and regional government paperwork, the Japanese year is retained. Japanese people and businesses have also adopted various conventions in accordance with their use of kanji, the widespread use of passenger trains, and other aspects of daily life.
The Philippines has not officially adopted any time and date representation standard based on the ISO 8601. Notation practices across the country are in various, customary formats.
This article is about date and time notation in Mongolia.