Talk:Calendar date

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[edit] Practical Advantages of the Format YYYY-MM-DD

The date format, YYYY-MM-DD, is not merely a format. It has significant practical advantages. Use leading zeros if necessary to make the Year 4-digit, and Month and Date 2-digit. Examples: 0023-10-25, 1987-02-09, 2007-01-23. If only year and month are relevant, use YYYY-MM. Examples: 1989-06, 2007-01.

  • 1.) This format can be written and understood by anybody regardless of the languages he/she knows and uses (You can still orally present it anyway you prefer).
  • 2.) The Year-Month-Date order is more logical than other formats in most cases, as one usually identifies a specific date in that order.
  • 3.) This is very important. In this digital age, many people routinely deal with computer files by displaying their filenames on the screen or process them in chronological order. When you organize files of data, which could be numbers or images, time (year and/or month and/or date) could be a factor that either naturally shows up in your file names, or you could put it in your file names purposely to your advantages.
i.) Thus if you create your data, your blog or diary for instance, on a daily basis, you can simply assign the date to the file names, e.g., 2006-05-06, 2006-07-23. If you organize your data on a monthly basis, use names like 1987-03, 1993-05, etc.. When you display them on your screen, they show up in natural chronological order. If you use codes, such as FORTRAN codes, to process these files one by one in natural order, it makes your coding much easier.
ii.) If the time alone in a file name does not give you enough information to remind you what is in the file, you could add different suffices, to the file names, which will not disturb the chronological order of the files. If beginning a file name by a number makes you feel uncomfortable, you can add an identical prefix before the year. Thus, you could have file names like y2006-01-01-party, y2006-01-02-shopping, y2006-01-03-piano-lesson, etc.. If you don't like the dash, "-", you can use the underline, "_", in place of it. Or you can eliminate the dash all togher.
iii.) Never use 2-digit years, 1-digit months and dates in file names in any order other than the above suggested format; never use non-digital month names, such as jan, january, feb, or february in file names, which will cause you lots of inconveniences for later archival or processing purposes.
  • 4.) This format is consistent with ISO 8601 which has more information about formats of time. --Roland 08:45, 6 January 2007 (UTC)

[edit] US Bias

I would like to point out that there is some major bias towards the US in this article. It clearly covers many different date format for throughout the world, however, it uses many examples of how the date is formally written or spoken, that are very rarely used in many countries other than the United States.

For Example:

  • In the Uk, Australia and New Zealand the majority of people say: The 5th of March, 2006. It is very rare to hear somone say 5 February 2006, as the later does not make any sense, it implies that there are 5 seperate Februarys. This also is the same for February 5, implying there was a February 4 and a February 3, etc, but this makes no sense either as there has been millions of Februarys since the begining of the Georgian callendar and there is no use in counting them all.
  • The use of these other formats make no sense, are inapropriate to use to determine a date in time, and are somthing that is used primarily in the US. The majority of the English speaking world can speak English properly, so thats the way it should be in the English Wikipedia, the correct way.144.132.17.88 02:11, 5 September 2006 (UTC)
    • This is a moronic argument, it makes sense, it is understandable to anyone when the date is spelled out. I dont do it this way and you dont do it this way, hundreds of millions do and it works quite well. As for your argument about there having been millions of Februarys since the introduction of the georgian callendar...... this means it has been millions of years since its introduction. Are you taking the piss?
  • The American way is odd. When you want to know what the date is, you most likely want to know what day it is as that changes more than a month or year does! You're most likely to forget what day it is than what month or year it is.

[edit] Miscellaneous

I would like to show a minor view of mine on writting of today's dates. I am fully awared with ISO 8601 standard. Recently I prefer to writte dates in these Mayan like form.

For example dates of current week I write:

0 Sunday   [2002.02.24]
1 Monday   [2002.02.25]
2 Tuesday  [2002.02.26]
...
6 Saturday [2002.03.02]

It is strange, yes - but ISO 8601 in a sence goes the same way. Mayan have two weeks with different number of days and I know why they write in such strange form which is, astronomically speaking, perhaps the best and the righteous one. We have only one week, with 7 days, first would be numbered as Mayan do 0. And all in brackets ([]) is noncycleing but linear increasing numbers for years, set of 12 months with selection from {28,29,30,31} and of course in the end - days all numbers in decimal system. Mayan used kindly different number systems. How long will it take we will adopt ISO 8601 in fully. I am sometime nowadays all confused. What do you think?
XJam following ISO 8601 let us write just 2002-27-02 where leading zeroes must be written. ** This is not ISO !! ** *** Yes you gotcha me, of course 2002-02-27 is correct - that is what I was talking about -- confusions, sorry --XJam 6 Saturday [2002.03.02] (0)***

If you think of it, the Mayan, the ISO, the Chinese, the Japanese simply use the natural way to tell time, i.e. in a natural progression from the longer to the shorter period, naturally, year, then month, then day, then hour, then minute, then second. Even the European notation of Day, Month, Year is natural but just in the opposite order. Only the US tries to be different and put in the Month, Day, Year unnatural order.

So one can start the week on a Sunday, but number the other days of the week by the number of days it comes after Sunday.

Sunday 0, 
Monday   1, Tuesday 2, Wednesday 3
Thursday 4, Friday  5, Saturday  6.

This looks like a compromise between starting the week on Sunday (actual start) and starting the week on Monday (numbering of non-Sundays).

If one starts with week with a Sunday then a symmetry occurs around the year 2000.

Below for each year, I list the number of days in the part-week at the start of the year, the number of whole weeks within the year, then the number of days part-week at the end of the year.

1997 4 days + 51 weeks + 4 days
1998 3 days + 51 weeks + 5 days
1999 2 days + 51 weeks + 6 days
2000 1 day  + 52 weeks + 1 day
2001 6 days + 51 weeks + 2 days
2002 5 days + 51 weeks + 3 days
2003 4 days + 51 weeks + 4 days

This symmetry applies to all years not just those listed e.g.

1900 6 days + 51 weeks + 2 days

2100 2 days + 51 weeks + 6 days

For weeks beginning Monday or any other day of the week, there is no such symmetry around any year at all.

User:Karl Palmen


Uph Karl, very interesting indeed. I must say I do not uderstand your table in full. Can you please give some more explanation on it? What really (2002 5 days + 51 weeks + 3 days) means? Does this mean that current year 2002 has 51 weeks and ('plus what)?

Yes I have understood that correctly. Thank you Karl for clearing this out. This year's 2002 first part-week is:

[2] Tuesday   [2002.01.01]
[3] Wednesday [2002.01.02]
[4] Thursday  [2002.01.03]
[5] Friday    [2002.01.04] and the last day of the 1st part-week
[6] Saturday  [2002.01.05] --> and all together is 5 days.

Then we have 51 "ordinary" weeks and the last part-week:

[0] Sunday    [2002.12.29] (First day of the last part-week :-)
[1] Monday    [2002.12.30] and finally 
[2] Tuesday   [2002.12.31] --> that gives us 3 days

so 2002 have: 5 + 51*7 + 3 = 365 days.

Nice. --XJam 1 Monday [2002.03.04] (0)

Correct User:Karl Palmen

Strange property of Gregorian calendar, don't you think and hard to calculate days between events in it, too. On my desk working calendar there is written that 2002 has 52. working weeks (fixed day (or closing date) weeks again according to ISO 8601) and 1st working week of 2003 starts on 1 Monday [2002.12.30]. 1st working week of 2002 starts again on 1 Monday and that is [2001.12.31]. In fact I do not like Gregorian calendar a lot, but I must use it. Tzolk'n is much much more thoughtful and who knows more usefull. I do not like Gregorian calendar too because astrologists calculate their strange horoscope and fated tables from it, and they say they're some experts on something that doesn't exist, astronomicaly speaking. (I mean a sky map, which because of precession of equinoxes does not fit with a real one and such). --XJam 5 Friday [2002.03.01] (0)

Astrologers would may also get it wrong if they use the Gregorian calendar literally. For example the start of the sun-sign of Aries is reckoned to occur at at the March equinox and also on March 21, yet in 2096, the equinox will be on March 19. --User:Karl Palmen

  • I have no problem with using ISO 8601 for dates and times, even though the usage in relation to days of the week and linking weeks to years seems a bit strange. The purpose of a standard is to get everybody to mean the same thing when they write. I can't say that I understand the references above to the Mayan calendar - but that's the entire problem with it: few people will. It must be added too that the numbering of the weeks and the days in the week has a limited application outside of finance. A day can be completely defined without knowing what the day of the week is. Using the Gregorian calendar has absolutely nothing to do with the validity of horoscopes. I don't need to believe in God and Jesus to accept that we are in the Gregorian year 2002. Eclecticology
    • Yes for days there's enough ISO codeing. It is enough although a little bit hard to calculate it by hand. We humans like to calculate by hand(s) which have 10 fingers, so not too long week is just fine for us. It is very human, as we say, why to be symple if it can be complicated and so Mayan combined Tzolk'in and Haab where there are in Tzolk'in 13 numbered days intermeshed with 20 named days and in Haab or vague year is a 365 day period of 18 months of 20 days each, followed by one 5 day period (Wayeb). Now days are harder to calculate.

      I've forgotten to say that above record is just my personal view and a little bit of self contentment. I am not trying to change any present or future standards. About Mayan there is not so much to understand in fact. Their calendar is so symple and yet so 'almost' perfect. With the 13th (leading) Mayan's cycle or bak'-tun I just wanted to emphasize their believes in cycleing of time - posible property of real (cosmological) time - which is not implemented in our year's notation. They had used a term similar of our year (Earth's revolution around the Sun, tropical year) in 3rd place of their notation as tun from bak'-tun. For shure they must had been awared in some way of Earth's revolution. Recently I've translated and adopted (now perhaps famous) John Major Jenkins' article The How and Why of the Mayan End Date in 2012 A.D and I must say his researches in this field persuaded me about general significance of Mayan calendar system of far past and of imminent present time, because we are heading toward such strange years as Clarke's 2001, Clarke's 2010, Mayan's 2012, Clarke's 2061 are. Their calendar, according to our present knowledge of Mayan's astronomy, was derived almost entirely from horizont astronomy mainly by observing the apparent motion of 'planet' Venus and Sun and such.

      I agree about validity or non-validity of horoscopes. But they (Greek or Chinese one at most) are 'studied' mainly in Western calendar system (Julian, Gregorian). Mayan also used (mainly Tzolk'in) to do 'horoscopics' and their descendant in Jenkins' 'dream land' Gvatemala still do. But hereby I do not want to say no other words about 'horo-hocus-pocus' because I respect all what Samuel Beckett had said on this topics.

      I also agree and salute natural progression from longer to shorter period of any calendar. Yes strange why Europeans like smaller things first. Americans must have heard to put a year on the last place from Indian natives, ha, ha. Legalisation fi di ganja herb - Do you love the music, yeah, reggae music ruffin' inna Japan Salute and out. --XJam 6 Saturday [2002.03.02] (1st ed.)

In Japan, all official documents are required by law to use the Japanese imperial calendar date format. For example, the year 2001 is known as Heisei 13 (平成１３年). Similar, in Taiwan, the year 2002 is known as Min-guo 91 (民國九十一年).

Can you justify this is true? Where did you get this idea? -- Taku 03:04 Feb 26, 2003 (UTC)

The British consider words and locutions that originated in England and died out in England "Americanisms". So it is with date formats. Traditionally, the English used m/d/y (see any reasonably old book written in England). Recently (100 years or less) they have begun importing the d/m/y format from the Continent, and so of course they call their own traditional m/d/y format the "American" date format. 131.183.84.166 23:45 28 May 2003 (UTC)

Can you justify this? Could you give an example of an English text where the m/d/y format is used for a date? Phantomsteve 12:32, 29 January 2006 (UTC)

Transition dates near start of calendar:

What about giving an example of one of the dates from the period when the calendar was being adopted and the new year shifted (from March to January), resulting in year formats such as 1680/81, to mean 1680 if new year is counted in March, but 1681 if new year is counted in January ?

[edit] Proposed style change

Wikipedia:Manual of Style (dates and numbers)/proposed revision 1) proposes "BC" and "AD" (in contrast with "BCE" and "CE") as standard for Wikipedia, 2) apparently encourages linking of years, and 3) encourages linking of units of measurement, among other changes. It also reverses the style of many of the dates used within the guide (such as "February 12" to "12 February"). See Wikipedia talk:Manual of Style (dates and numbers) for discussion. Maurreen 01:46, 24 Jan 2005 (UTC)


[edit] Date systems

moved from Wikipedia:Reference desk/Miscellaneous

Why does the American date system follow a MM/DD/YYYY pattern as opposed to DD/MM/YYYY. It seems counter intuitive (there is no order to it) but presumably there must be some logic behind it. smurrayinchester(User), (Talk) 16:55, 15 November 2005 (UTC)

It's possibly a shortening of the spoken form - "When's your birthday?" "April seventeenth"? Shimgray | talk | 16:58, 15 November 2005 (UTC)
Yes but that doesn't really give any more information; the European format would be a shortening of "the seventeenth of April" but the question is, why is there a difference in order in the first place? I'm curious about this as well. —David Wahler (talk) 22:57, 15 November 2005 (UTC)

Hey, it's just the way of our people! You gotta problem wit dat? alteripse 00:00, 16 November 2005 (UTC)

That would make our work here quite easy. Just answer to every question "well, that's just the way it is". :)
But about the question, the Calendar date article mentions the phenomenon, but doesn't give a reason. It mentions only in passing that this is a matter of endianness (which I will amend in a moment). The European format is little endian (it starts with the smallest order of magnitude). The US format is middle endian, which is as odd as the term. But the most logical (well, consistent anyway) method is big endian because that's how our numbering system works. Take a number, say 2005. That starts with the highest order magnitude, the thousands, and then the hundreds, tens and 'singles' (what do you call that?). So it would make sense to extend that to the date format.
Note that I haven't answered the question either, but at least I've made an effort. :) DirkvdM 12:50, 16 November 2005 (UTC)
It seems to me that its natural in English to use a noun as an adjective (as in "New York style") rather than to use a genitive ("the style of New York") when both options are available. So "November 16" rolls off the tongue easier than "the 16th of November." But a year can't act as an adjective, so you have to say "November 16, 2005." The M/D/Y order comes from the way we speak. -- Mwalcoff 07:46, 17 November 2005 (UTC)
Again you're forgeting the differences between English and the American dialect of English. Current English use is to use prepositions to signify ownership, so, in English, "16th of November" would be correct. We would also say "16th of November, 2005". --86.15.129.99 22:07, 12 July 2006 (UTC)
That explanation coincides nicely with the habit of saying '16th of November' in stead of '16 November'. I've always found the former a bit odd (in the Netherlands it is occasionally, though rarely, used, and feels a bit archaic). But if you regard the day as a property of the month it makes sense. Then again, one might just as well call the month a property of the day since any month has a day 16. But to me it's all a series of numbers used to pinpoint a day and there's no order other than the order of magnitude. I suppose it's more than anything a matter of standardisation. Which method is used doesn't matter much as long as everyone uses the same one. Which is developing into a problem in this internationalised world. So someone is going to have to adapt. And since that will create a grudge on the part of the minority (the M/D/Y users) a neutral third international standard might make sense, namely Y/M/D. Which incidentally gives the M/D/Y users their way where the year is left out. I've already started using it. DirkvdM 08:49, 17 November 2005 (UTC)
I hear rumors that an early FIPS standard recommended doing it that way (m/d/y, with a 2-digit year), and briefly mentioned that in the article. I suspect there isn't any good reason for doing it this way, and I hope it's not too late to switch to a superior system. --DavidCary 21:58, 18 November 2005 (UTC)

[edit] RFC-2822 date style

this style is commonly used in computering: Sun, 8 Apr 2007 20:57 +0000

–AzaToth talk 16:10, 25 November 2005 (UTC)

[edit] Norway (yyyy-mm-dd) ?

62.16.202.221 18:57, 20 August 2006 (UTC) Daniel (unregistered)

I am a Norwegian and I have never heard, or seen, that we use year-month-day. I myself only use dd/mm yyyy or dd.mm.yy, and I beleive most offical use dd.mm.yy too (see Odin.no) Please give me a source that confirms that Norway officially uses yyyy-mm-dd and not dd.mm.yy

I have a similar issue regarding the fact that Austria was placed under the yyyy-mm-dd list. I have lived in Austria all my life and haven't ever consciously seen this used. It would also not agree with the German language, as one says 12te Mai (12th May) and it is literally impossible to say Mai 12. Also, the main Autrian television broadcaster has on its teletext, Sa, 9.09.2006, so i believe this is actually the proper form.

[edit] Germany (dd/mm/yy)? No! It's "d. month yy"

I am German and I have never heard or seen that we use Slashes ('/') in a date. Slashes means for me that I have to watch out carefully and expect a US ("middle endian") mm/dd/yy (or even worse mm/yy) format. In Germany we write dd.mm.yyyy (with or without leading zeros, some people are lazy and write yy instead of yyyy. See also de.wikipedia.org:Datumsformat.

I really prefer the ISO way (yyyy-mm-dd) because xxxx-xx-xx has to be yyyy-mm-dd because I've never seen someone using yyyy-dd-mm. But it will take ages to change the mind of the people (remember metric system is international since the 70's). --Knarf

There was definitely someone trying a bit of POV and convincing others of something that is not the case. Reading newspapers and watching television, there is really no one using dashes at all, and the year comes last as well. --FlammingoParliament 14:02, 17 November 2006 (UTC)

right. metric is international, but I am from Canada, and have always used the yyyy/mm/dd. This is the most logical means of dating. Largest to smallest, and that is how metric system works too Largest unit to smallest.—The preceding unsigned comment was added by Eaglegordon (talk • contribs).

Germany, not Canada --FlammingoParliament 20:23, 23 November 2006 (UTC)

[edit] external links

removed * Easy Date Converter Windows software for conversion of Gregorian, Julian and ordinal dates and for calculations with them as it is available at the bottom of the other link to hermetic.ch

[edit] Long Format date

Is there any usage of ISO8601 while writing long date format. I know that ISO concerns only in numeric representation.

[edit] Historical Background?

It would be interesting to know the historical background behind why various countries chose various formats. Some it is by chance, to be sure, but there must have been a very specific reason why the UK suddenly reverted to day month year around 1900, whereas the USA did not. Any insights there which could be integrated into the article?

[edit] USA- M/D/Y

why does usa use month day year, if they are a product of britain, and britain uses d/m/y

- I do not know why we use m/d/y but we split from Britain 225 years ago. (Which is why we put appointments on our calendar and they put it on their diary.) I would love for US to move to a more international standard but which one - y/m/d or d/m/y?

[edit] Today's date is...

Can you please remove the one-line "current date" paragraph? If not, please justify it here and clean it up. It is very ugly and doesn't belong in an introduction to an encyclopedic article. (It's also wrong - today is the 16th, not the 15th.) 4.242.147.161 03:03, 16 January 2007 (UTC)

I've rephrased it slightly to reflect a redirection to the current date. Bobo. 03:09, 16 January 2007 (UTC)
As far as I know we now have a red link to an article which should not exist (we don't have articles for individual days). And it points to a new article name every day. I wonder how many of these wrongly-named articles have been created by innocent newbies ... -- Chuq 23:17, 16 February 2007 (UTC)
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