Different conventions exist around the world for DATE AND TIME REPRESENTATION, both written and spoken.
* 1 Differences * 2 ISO 8601
* 3 Local conventions
* 3.1 Date
* 4 See also * 5 References
Differences can exist in:
* The calendar that is used. * The order in which the year , month and day are represented. (Year-month-day, day-month-year, and month-day-year are the common combinations.) * How weeks are identified (see seven-day week ) * Whether written months are identified by name, by number (1-12), or by Roman numeral (I-XII). * Whether the 24-hour clock , 12-hour clock or 6-hour clock is used. * The punctuation used to separate elements in all-numeric dates and times. * Which days are considered the weekend .
Main article: ISO 8601
International standard ISO 8601 (_Representation of dates and times_) defines unambiguous written all-numeric big-endian formats for dates, such as 1999-12-31 for 31 December 1999, 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
ANSI INCITS 30-1997 (R2008), and FIPS PUB 4-2 in the
See also: Category: Date and time representation by country
Main article: Date format by country
Many countries use the ISO YYYY-MM-DD date format generally, and they have the advantage of being unambiguous. (YYYY means four-digit year, MM means two-digit month, and DD means two-digit day.) Local conventions can vary, and for the commonly used Gregorian calendar "> When speaking, a person may often pronounce time in 12-hour notation, even when reading a 24-hour display. It is also common that a person uses the 24-hour clock in _spoken_ language when referring to an exact point in time ("The train leaves at fourteen forty-five …"), while using some variant of the 12-hour notation to refer vaguely to a time ("… so I will be back tonight some time after five.").
In certain languages such as Portuguese , Dutch , English , Czech , and Hungarian the hour is divided into quarters and halves, spoken of relative to the closest hour.
In many Germanic languages the half-hour is referred to the next hour ("half to nine" rather than "half past eight"). In colloquial language, this can cause confusion between English and German, Dutch or Swedish diction: in conversational English as spoken in the UK, "half past eight" (for 8:30) is often reduced to "half eight", while in German "halb acht", in Dutch "half acht" and in Swedish "halv åtta" invariably means 7:30. For the quarters, 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").
In the French language , 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"). The separator between hours and minutes is the letter h (18 h 45, for example).