Talk:24-hour clock

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[edit] Analog 24-hour clocks

There are analog clocks and analog watches that display the time using the 24 hour clock. In fact, ever since the very first clock face was designed, there have been 24 hour analog clocks. Harrison's H1 chronometer, for example, has a 24 hour analog dial. After about 1500 to 1600 CE. this type of dial was used primarily for scientific and technical use.

Pete Boardman

Yes there are. Also there are clocks that chime for the whole 24 hours. I would assume they would chime 24 times for 00:00 rather than nothing at all. Borb 10:55, 13 August 2005 (UTC)

[edit] 24:00

Reason for my edits:

the day begins at midnight, 00:00 (12:00 am), and ends at 23:59:59
There is no 24:00

Not strictly true: 24:00 (otherwise 24.00, 2400, etc.) is frequently used, for example in railway timetables, to denote the end of the day. A train due to arrive at a station during the last minute of the day is shown as doing so at 24.00; a train due to depart during the first minute of the day is shown as doing so at 0.00. -- Picapica 16:54, 2 Oct 2004 (UTC)

I thought of adding a note on alternative notations: 1234, 12.34, etc. for 12:34 - but perhaps this would be needlessly confusing? -- Picapica 17:22, 2 Oct 2004 (UTC)

I have sympathy for keeping the notations restricted to the hh:mm and hhmm styles. These are the ones defined in ISO 8601. Of the others, only the one lacking the leading zero for the hour is widely used (now also mentioned). The problem with hh.mm (the old official German DIN 1355 notation, before it was replaced by ISO 8601 in the mid 1990s) is that it is easily confused with a decimal fraction, and the fact that ISO 8601 also allows decimal fractions of hours (e.g., 10.50 = 10:30). So the colon is a good reminder that this is a base-60 notation, whereas dot and comma indicate base-10 notations. Markus Kuhn 14:00, 19 Jun 2005 (UTC)

Isn't the last minute of the day 23:59? 24:00 would be exactly the same time as 00:00 on the following day? It is interesting to me that the train time-tables use both 00:00 and 24:00.

Train time-tables used to avoid 00:00 altogether in order to reduce confusion. That may have changed, of course. --Palnatoke 09:33, 9 Nov 2004 (UTC)

I've never seen 24.00 on a railway table, and I have seen 0.00 on a tram table. The times were on a "stem-and-leaf" type table, and it would look out of place to have a "24" hour with just one entry. However, "0-24" is common to indicate 24 hours; one subtracts the left number from the right and gets 24. Also, wrap-around is common, e.g. a restaurant might say 10-03; as an American, I remember being initially confused by that in Europe... I was at a restaurant at 9pm and was surprised it was open. EventHorizon talk 05:55, 8 Feb 2005 (UTC)

I've never seen 24:00 on a railway timetable either. On a side note, further down the article (unrelated to the section about timetables) it says midnight is "24:00", surely it's 00:00. -- Joolz 22:31, 19 Mar 2005 (UTC)
I noticed the other day that my kitchen cooker goes to 24:00. -- Joolz 22:24, 2 Apr 2005 (UTC)
And then the cooker clock moves on to 00:01?, just curious −Woodstone 21:00, 2005 Apr 3 (UTC).
Yeah, I found it weird too. -- Joolz 00:32, 4 Apr 2005 (UTC)

I just checked my railway table and it has occurrences of both 00:00 and 24:00. Since midnight is the boundary between two days, it can be expressed as the end of one day or the beginning of the next. −Woodstone 23:48, 2005 Mar 19 (UTC)

Not sure about mentioning both 00:00 and 24:00 in the bullets at the bottom: we just mentioned digital watches above, and none of them show 24:00. I've only ever seen 00:00: I think 24:00 is pretty rare and only used in certain cases such as the trains. Turnstep 20:31, Apr 8, 2005 (UTC)

Both 00:00 and 24:00 are part of the ISO standard defining the international notation of date and time, so it makes sense to mention both. If I might guess, I think seeing 23:58 in print is more rare than 24:00. Of course I did not expect ever to see it on a clock (such as Joolz's cooker). A clock has to make a choice and surely 00:00 makes more sense, since it would stay displayed till 00:00:59. −Woodstone 20:50, 2005 Apr 8 (UTC)

I've added a picture of the cooker showing the time 24:00, unfortuantly it's quite low quality. I'll try and replace in a few days with a high quality one. -- Joolz 00:20, 9 Apr 2005 (UTC)

Replaced :> (OK, a bit longer than a few days, but still.) -- Joolz 20:10, 8 Jun 2005 (UTC)
I changed your caption to clarify that this image shows a curiosity and not the standard behaviour of most digital clocks, which count from 00:00 to 23:59 such that the wrap-over from 23:59:59.999 to 00:00:00.000 coincides with the start of a new day and date. Markus Kuhn 14:00, 19 Jun 2005 (UTC)
I recommend removing this image. As stated above, this is just an aberration, and will likely just confuse someone taking a cursory look at this article to learn about 24 hour clock. -Froese 06:47, 21 January 2006 (UTC)

In the military, I thought they just used the notation 0023 for example, not using the colon. I assume this is becasue when they talk over radio they would simply say four figures for the time like "zero zero two three hours". Borb 11:03, 13 August 2005 (UTC)

How is 24:00 different then 00:00? 24.237.198.91 10:26, 9 April 2006 (UTC)

For the same date 24:00 is 24 hours later than 00:00. So opening hours on a date could be 00:00 to 24:00. Stated otherwise 24:00 on one date is equal to 00:00 on the next date. −Woodstone 11:31, 9 April 2006 (UTC)

[edit] Usage by region/country/culture

I have moved all country-specific discussion into a separate section. I believe this is the only part of the article that still needs substantial work. Markus Kuhn 14:00, 19 Jun 2005 (UTC)

[edit] Leading zero for hours up to 9

The article was modified to state that a leading zero for hours up to 9 is not mandatory. That would then be the only place where leading zeroes are not mandatory (month, day, second must still have fixed number of digits). If the statement is true the advantage of easy (character based) sorting of date/time is lost. Can you elaborate? −Woodstone 19:25, 2005 Jun 19 (UTC)

Leading zeros are clearly not optional in the ISO 8601 notation (and probably also not in the U.S. military-style colon-free "hhmm hours" notation). However, this article is about the use of the 24-hour notation in general and not only about the ISO 8601 version of it, for which there is a separate article. The majority of people in regions where the 24-hour clock is the standard colloquial way of writing a date would certainly write "9:00" instead of "09:00". Most digital wrist watches in 24-hour mode show "9:00" instead of "09:00". I think this is plenty of evidence to support that using a leading zero for hours is not something strictly required for use with the 24-hour notation. It is only required by specific computer data formats, such as ISO 8601. Markus Kuhn 13:12, 18 July 2005 (UTC)

[edit] Make the Windows clock show military time?

Are there any freeware programs that can make the Windows clock on the taskbar display in military time? I looked on Google and couldn't find any. --pile0nadestalk | contribs 22:50, 17 July 2005 (UTC)

I've no idea, mine is set to display the 24-hour clock, and I haven't used any third party programs to do it (nor could I find the option in Windows either), you would be better off trying WP:RD for your answer. -- Joolz 00:15, 18 July 2005 (UTC)
Thanks, but I already did. --pile0nadestalk | contribs 00:46, 18 July 2005 (UTC)
I've had another look, and I've found it. If you're using XP, go to the control panel, look in "Regional and language options", click customize, choose the time tag, and use uppercase Hs. Hope this helps, Joolz 01:12, 18 July 2005 (UTC)
Good idea! I've added a brief section on this to the article. Markus Kuhn 13:56, 18 July 2005 (UTC)

It might be a good idea to include how to do it on other OSes like Mac OS X and Linux --pile0nadestalk | contribs 07:18, 31 July 2005 (UTC)

Windows shows military time by default if you select nationality as UK. It uses 12 hour if you select US. Its because a lot of americans don't know what a 24 hour clock was, and that reminds me of an anecdote. I was talking to an american once and I said "its 23:00 here, whats the time there?" and he was really confused. When I finally managed to explain 24 hour clocks he said "we have a much simpler system here, it uses only 12 hours and am and pm." lol. Borb 10:59, 13 August 2005 (UTC)

To change to the 24 hour clock in Windows XP go to Settings->Control panel->regional and language options. click on customize. Then pick the time tab. You will see a note on the bottom of the window concerning 24 hour time. just enter the time format as HH:MM:ss and presto it is now in 24 hour format.--stickman 01:18, 15 November 2005 (UTC)

[edit] Usage in UK

Is there a source for the paragraph about usage in UK where it says its not as universally used as other countries? I would say that every digital clock in my house uses either 24 hour by default or at least an option. All major news networks use 24 hour notation including BBC and Sky News. Teletext and Ceefax use it. I certainly use it if I can and I don't think any one doesn't understand it like a lot of people in USA (see my anectode earler on this page). I think what is said may be true but only half of the truth, it makes it sound like USA use 24 hour clocks more than UK which is not true. Borb 11:15, 13 August 2005 (UTC)

I've just rephrased both the US and UK usage paragraphs. Better now? Markus Kuhn 18:04, 13 August 2005 (UTC)
Yes, that's much better, thanks. Borb 13:51, 14 August 2005 (UTC)
Your droll little anecdote aside (who knew that a sample of 1 is statistically significant for a population of 300 million!), I note that The Guardian's website [1] for breaking UK news identifes the time of its last update with 12-hour clock notation. As does The Times's cinema listings. But maybe these aren't major news outlets? 64.198.252.184 04:16, 22 January 2006 (UTC)

Your example for spoken times (eg Birmingham) could usefully mention how times with hours 12 - 24 and no minutes are spoken. Perhaps more examples, eg from the BBC World Service, might be useful. "It's 3 hours, GMT". "The time is 17 hours, GMT, here in London". Cormullion 22:05, 28 March 2006 (UTC)

At Birmingham New Street, or for that matter any other National Rail station in the UK, you will find that no trains are scheduled to leave at 24:00/00:00 ever. If a train were to be at any station at midnight, it would be advertised as arriving at 23:59 and departing at 00:01. Pimpmytrain 05:05, 27 April 2006 (UTC)

I think more and better examples would be nice for UK spoken english. People don't speak like a robotic Birmingham New Street computer. People don't say "oh six fifty-nine", they say "six fifty-nine". People don't say "oh seven hundred hours", they say "seven o'clock", even if the same person would go on to say "seven oh one". --squish 00:20, 17 June 2006 (UTC)

[edit] Ambiguity

"The 24-hour clock enjoys broad everyday civilian usage in most Asian, European and Latin American countries, where it is almost exclusively used to write down times." -- This can mean that when writing down times it is almost always used, or it can mean that it is rarely used except when writing down times. (Actually, in Japan AM and PM are nearly always used except for some things like train timetables.) --Zero 14:16, 14 August 2005 (UTC)

"In written English, there is no conventional notation for indicating that a time uses the 24-hour clock. Therefore, any 24-hour time between 1:00 and 12:59 is ambiguous."

I disagree. 1:00 is distinguished as 12-hour because there is no preceding zero. 12:59 can only be 12-hour. It's only the times 10:00 to 11:59 that could be either. But, because in England 12-hour times are written with a pm or am afterwards, I think it is quite clear.
E9 | TALK | ROCKER!! | ROCKAB00M | TALK
I think the ambiguity is there in interpretation rather than implementation. For example, if someone handed you a note saying "Please meet me here at 8:00 tomorrow", you would have no way of knowing whether it was for breakfast or for an evening out. The presence or absence of a preceding zero doesn't really help (see the railway timetable in the article, for example): you don't know whether the writer has omitted the am/pm suffix from a 12h time or has omitted the leading zero from a 24h time. And while 12h-time users can add a am/pm suffix, 24h-time users can't add anything to 10:00 to say "this is 24h time". So writers can specify time unambiguously, but readers can't... That's my theory anyway :-) Cormullion 13:31, 3 February 2007 (UTC)

[edit] Potential problem

I find a potential problem with this article in that it seems like it is trying to say the the United States is all alone in its use of the twelve-hour clock system. While the article has a few exceptions to this, I think that it should be made clearer that other large countries still widely use the twelve-hour system. For instance, I have traveled to Canada before, and just about every where I've traveled in that country, the 12-hour system was in wide usage. The only exception to this that I could find was in the province of Quebec, where a modified twenty-four hour system is used. Times are written as, for instance, 18h03 rather than 18:03. This comes from Quebec's use of the French language. The h in 18h03 comes from the French word "heures" for "hours". I have also heard that Portugal follows this same format (where the h stands for "horas", the Portuguese word for "hours". However, I have also heard that Portugal only uses this format on a formal basis (like for trains and shows), and that the twelve-hour system is still used for many informal events and for verbally.

I agree. Not only that, but both here, and at the 12 hour clock page, the U.S. seems to be criticized for using the 12 hour system. No offense, but just because Europe jumps on the bandwagon, that dosne't mean we should too. That's what's so great about individuality. Pacific Coast Highway 05:47, 2 October 2005 (UTC)

I can't find any overt "criticism" of the United States in the current article. The article does explain in great detail the practical advantages of the 24 hour clock, and it does point out that the United States are rather unique in avoiding to expose the general population to it. While it is always difficult to criticise a convention, without implying criticism of its followers, to me the article seems to be a factually pretty accurate and adequate description of the current situation. If not, can you name any other industrialized country where the 12 hour clock notation is used equally universally, even on airline tickets and train timetables, or where a substantial fraction of the population is not even familiar with the 24-hour notation? Can you name any particular advantages of the 12-hour notation over the 24-hour alternative, that can help to explain and justify its continued almost exclusive use in the United States? Markus Kuhn 22:08, 4 December 2005 (UTC)
If you reread the first post in this section, you'll find that Canada, still an industrialized country as far as I know, also uses the 12-hour system. As do, according to the partner article at 12-hour clock, Greece and parts of South America.
I have to add, that in Argentina and some other latinamerican countries, the 24 hours system is used entirely, for formal dates, programs, calendars, etc, even notations. But when spoken people almost exclusively say "four in the afternoon" for 16:00.
As to advantages, the vaunted benefit of being able to avoid confusion over whether "12:00 p.m." stands for noon or midnight is perhaps dispelled by the remarks above regarding the uncertainty over whether midnight is correctly denoted "00:00" or "24:00."
I'd also point out that characterizing the situation as one in which the U.S. "[avoids exposing] the general population to [the 24-hour clock]" is not quite accurate, and perhaps smacks of patronizing. There is no conscious effort to spare Americans the difficulty of learning a new system, we simply use a different one. You know, the same way Germany "avoids exposing" Germans to avoirdupois pounds.
But I'll make you this deal: if you Continentals give up your fetish for grammatical gender, I'll personally see to it that every American abjures the hopelessly primitive 12-hour clock and its attendent burden of remembering that "12 p.m." is noon and "12 a.m." is midnight.
That is the main problem for me with the 12 hour clock, never been able to be really sure which 12pm/am is the 00:00 and which the 12:00
Lastly, I register an exception to asserting that most, or even a considerable plurality of, Americans are unfamiliar or unpracticed with the 24-hour clock. Care to provide some substantiation for the claim?
64.198.252.184 03:35, 22 January 2006 (UTC)

[edit] Psychological effects?

The "Psychological effects" section sounds dubious to me. Is this just the contributor's personal impression, or a well-documented phenomenon? Only the latter belongs into this encyclopedia. Unless someone can provide solid references, preferably to peer-reviewed scientific literature, that documents the claimed effect, I suggest to remove this entire section. Markus Kuhn 22:08, 4 December 2005 (UTC)

Now moved to talk page until someone can provide a reference. Markus Kuhn 16:38, 28 January 2006 (UTC)

"It has been suggested that the 24-hour clock, when contrasted to the 12-hour clock, has certain psychological effects in how the dual-system mind interprets it in accordance to the environment. Mainly found in countries such as the United Kingdom where the two systems lie side-by-side, it has been suggested that reading a time such as 3pm seems earlier in the day than 15:00. The reason for this can be explained in the way the mind interprets time. Whereas 3pm seems to suggest that there is a significant amount of time following it, and is early in the afternoon, 15:00 suggests that it is heading towards the end of the day, therefore making it appear later. This effect can be better demonstrated by changing one's own (digital) watch from 24-hour to 12-hour (or vice-versa) and interpreting the effects oneself."

[edit] 24:00:00

Does really rarely happen in the instance of a leap second having to be inserted into a year.

This usually happens at midnight and so an extra second is added making 24:00:00.00 before the standard roll over to 00:00:00.00

No, as mentioned in the article, the correct notation for a positive leap second is 23:59:60 (see also leap second#Announcement of leap seconds). Alureiter 02:06, 19 January 2006 (UTC)


With regards to the picture of a clock showing 24:00, it looks more like someone is setting a countdown timer for 24 hours of time rather than trying to depict the actual current time. - fooflington

[edit] Japanese Use

I've recently noticed on many TV schedules and train timetables that times are listed between 05:00 and 28:00 - probably in an attempt to cater for those who stay up all night, but I've never seen this usage anywhere else so I don't know if this is a Japan-only thing. Also note that in Japan, AM and PM come before the time, and not after (eg, AM8:00~PM10:00). --PkerUNO 09:55, 2 April 2006 (UTC)

[edit] Different separation characters

In Sweden, the land of my fathers, we use a point for separation of hours and minutes, i.e., "12.34". Some Ukranian friends also told me that they usually write "1234". (In neither case I know what happens when it comes to seconds.) The article should probably mention different notation standards and where they are used. I'm afraid I know nothing more than what I have told you already, and don't have any reliable references for backing even that up. Bromskloss 12:46, 24 April 2006 (UTC)

In Germany, it used to be the dot as well (DIN 1355, DIN 5008), as in "12.34". The German standards on this were changed (in the case of DIN 5008) in about 1995 to the colon, as in "12:34", in line with how ISO 8601 does it, or replaced by DIN EN 28601 (in the case of DIN 1355). Soon afterwards, the colon started to show up in widely used style guides (e.g., the one in the Duden). The house styles of some individual German publishers might still follow the old (1950s) DIN 1355 time notation with dot; such things take time to catch on. I'd not be surprised if the situation in Sweden (and other European countries) is actually similar, i.e. that the formal standards switched already from dot to colon, but that such a change has not yet caught on universally. Do you have information on current Swedish standards and style guides on the matter? Markus Kuhn 20:22, 24 April 2006 (UTC)

[edit] Speach

in English the spelling for 0 is o not oh as stated in the article. sorce THE OXFORD AMERICAN COLLEGE DICTIONARY. Zginder 16:14, 6 May 2006 (UTC)

In English the spelling for "speech" is "speech" not "speach" as stated in the header of this section. source SUCCESSFUL COMPLETION OF THE THIRD GRADE.

[edit] History

One day I'll add some history about this topic. You can find more at 24 hour analog dial at the moment, but I think it would be interesting to have some information about usage over the centuries.

The earliest primary source I have traced so far is a manuscript written in about 1350, MS Ashmole 1796. Part of it is reproduced on page 186 of John North's book about Richard of Wallingford "God's Clockmaker". It shows a chart of the numbers 1 to 24, arranged on a grid and showing a how a clock mechanism could be designed to strike the number of hours (1 to 24) without a 300 peg hour striking wheel. So at the moment the first recorded usage of the 24 hour clock is from - England... Cormullion 20:29, 9 May 2006 (UTC)

[edit] Neutrality

Does not mention disadvantages only the advantages. I could see how it lest two of the sme points under advantages could be used under disadvantages. Zginder 19:38, 7 May 2006 (UTC)

Hi Zginder. I'm sorry to say I did actually delete one of your comments under Disadvantages, but it was the one when you said the 24 hour clock system is French. This is not only untrue, in my opinion (Egyptian or Italian I would accept :-)), but also I don't think you could argue that being French was a disadvantage... I thought that your comment about number bases was true, but I couldn't quite see how relevant it was to the 24 hour system that you can't divide 60 by an integer to get 24. It has some relevance to the design of 24 hour analog dials, but that's another topic... (I didn't delete that one.) As for the two midnights objection, I didn't think that made any sense, although I didn't delete it. There are two midnights, embracing the day, so why not a proper unambiguous notatation for them...?
I do, however, agree with you that the sentence "The United States and Canada are the only industrialized countries left in which a substantial fraction of the population is not yet accustomed to it." could be improved to convey a more neutral opinion. It's the use of the phrases "the only industrialized countries left", and "not yet accustomed"... These are plainly loaded phrases, implying "they're lagging behind", "they should know better", and "they need educating", which certainly undermines the article's neutrality. And I'm a 24 hour clock zealot...
I think there are some disadvantages, too, but I think these are mainly in the realm of pronouniciation and speech, due to the fact that English is both the world's lingua franca and the least 24-hour-friendly language. Cormullion 17:28, 8 May 2006 (UTC)
The article does say it is called continental time in the United Kingdom and there are no English speeking countries on the of mainland Europe. It is French. The Egyptian had a 12-hour clock. Zginder 19:42, 8 May 2006 (UTC)
A leading zero is inefficient. Zginder 19:48, 8 May 2006 (UTC)
It is childish to think that there are two midnight in a day. That would mean two points in time with the same name right after one another. The day begins with midnight. The day ends right before midnight. Also, it is customary that the time interval associated with a given time display is closed at the start and open at the end. If we accept that convention, then it only makes sense – in the interest of consistency – to also interpret the time intervals denoted by the period of a day as closed at the start and open at the end. In other words, "day" covers the interval [00:00, 24:00) Zginder 22:04, 8 May 2006 (UTC)
I really like the last sentence, showing how useful it is to have an expression (24:00) for midnight at the end of the day. −Woodstone 11:12, 9 May 2006 (UTC)
I only used the 24-hour clock above because this article is the 24-hour clock. Hah! Your wrong. Zginder 22:07, 22 July 2006 (UTC)

[edit] Consistency between 12-hour clock and 24-hour clock

Can we ensure that there is consistency between 12-hour clock and 24-hour clock? The issues are almost identical but the articles are inconsistent.

Perhaps we should have a single article. bobblewik 07:27, 15 May 2006 (UTC)

The overlap is mostly in the "Use by country" section, which was copied recently. I suggest we move that entire section into a separate article date and time notation by country and leave only 2–3 summarizing sentences in the article. Markus Kuhn 13:47, 15 May 2006 (UTC)
It was me that copied 'Use by country' in. That was just one area. I don't think we can solve it by pulling sections out one at a time. See 'advantages/disadvantages', 'Typography', 'Criticism'. Content is almost entirely comparative and not unique.
I propose a parent article called 'Time formats'. bobblewik 17:57, 15 May 2006 (UTC)
No that would change the fact the Americans and Canadians should edit the 12-hour clock and everyone else the 24. That is how it should be, thou it isn't. Zginder 22:07, 22 July 2006 (UTC)

[edit] Australia - Double negative

"It is unlikely that Australia will never migrate to 24-hour notation." What did the author intend to say? I assume it was "...will ever...", but I've nothing to back it up. (unsinged, copied from 12-hour clock by Zginder 13:32, 27 July 2006 (UTC))

[edit] Cites for 6 hour clock in other East African languages?

24-hour clock#Other regions: Found cites for Swahili using a 6 hour clock with the day starting at 0600, but still looking for some of the other "many East African languages" that are claimed, including some spoken in Ethiopia, which is claimed in 12-hour clock#Ethiopia. TransUtopian 02:52, 3 August 2006 (UTC)

The entire 6-hour clock topic is rather off-topic for this page and should really be moved instead to Date and time notation by country, IMHO. Markus Kuhn 13:43, 3 August 2006 (UTC)
Done. I didn't fully realize they're actually on a 12 hour time clock, simply offset by 6 hours from ours. I'm still looking for evidence that other East African languages have this custom as well. TransUtopian 15:13, 3 August 2006 (UTC)

[edit] Is 24:00 really that rare?

I saw the picture of the cooker on this article about a year ago, but just recently noticed that my oven does the same thing (how often do you look at your oven at midnight?) It is a Neff[2] oven, so it's probably safe to assume all Neff ovens, at least in that era do the same thing. Neff is a popular make for an oven, and it's in the same group as Bosch and Siemens. Can anyone confirm any other ovens that display this behaviour? -- Borb 23:20, 4 September 2006 (UTC)

Exact model number and ROM version? I'm tempted to email them a bug report ... ;-) Markus Kuhn 09:02, 5 September 2006 (UTC)

In MacOS 10.4.8 you can choose from the following formats for hour: 1-12, 01-12, 0-23, 00-23, 0-11, 00-11, 1-24, 01-24. Choosing the last of these will display midnight as 24:00, and continue using 24 up to 24:59... Perhaps it's for compatibility with late-night cooking sessions... Cormullion 09:48, 18 October 2006 (UTC)

My cooker does the same. I know it's not Neff, but I can't recall the make (not whilst I'm at work anyway). Definitely displays 24:00 for one minute at midnight before changing to 00:01. It never displays 00:00. Perhaps the part in the article that says "Digital clocks run from 00:00 to 23:59; this means they never show 24:00 on their display. This way, the roll-over from 23:59:59.999 to 00:00:00.000 coincides with the start of a new day and date." should be changed to read something like "Most Digital clocks run from 00:00 to 23:59; meaning they never show 24:00 on their display (although some instances that do show 24:00 have been found, for example, on common brands of cookers, where the 00:00 is not displayed). This way, the roll-over from 23:59:59.999 to 00:00:00.000 coincides with the start of a new day and date." GC.

[edit] 24 time does not have ":"

Sources [3] [4] [5] [6] [7] DXRAW 23:29, 17 January 2007 (UTC)

The colon-free 24-h notation is indeed characteristic of U.S. military usage (see your references), UK railway usage and some computer formats. However, im most other uses (e.g., email headers, television in Europe [8][9] and elsewhere, digital wrist watches, even Wikipedia) in everyday civilian live in many countries, the colon (alternatively in some countries also a dot on the line) is used. I find it increases readability. Both the colon and colon-free notation are covered by ISO 8601. I will therefore revert your removal of the colons from the conversion table, as it does not reflect the most common (or IMHO even most readable) variant of the notation. Markus Kuhn 09:51, 18 January 2007 (UTC)

[edit] Pronunciation

How do you pronounce the times of the 24-hour clock? There is a pronunciation section at 12-hour clock; why not one here? I am confused and would like that information on the 24-hour notation.142.176.114.191 03:06, 14 February 2007 (UTC)

Are you suggesting that we rename the existing section "The 24-hour clock in spoken English" into "Pronounciation" or are you saying that anything important should be added to that section? Markus Kuhn 09:31, 15 February 2007 (UTC)

[edit] New "disadvantage"

I have taken the liberty to be bold, and I have added this disadvantage:

“ In terms of pronunciation, a specific 24-hour notation time such as "19:59", said as "nineteen fifty-nine", may sound too similar to and be mistaken as the calendar year 1959. Though this issue has been nonexistant since 1960, it may resurface after 2010, when the pronunciation "twenty ten" (20:10) may become more prevalent than "two thousand ten" (2000–10). ”

If anyone finds it inaccurate or misplaced, please discuss here. Thank you. — 142.176.125.209 00:05, 16 February 2007 (UTC)

In English, different prepositions used for years and times-of-day can help to resolve the ambiguity: "It was a snowy Sunday evening in 1959 when I heard at 19:48 a loud bang on the door ...". In some other languages, there is a well-established short word spoken in place of the colon, such as "19 Uhr 59" in German and "19 heure 59" in French, which denotes as unambiguously a time-of-day as am/pm do in English. I guess the equivalent "19 o'clock 59" won't succeed in English because "o'clock" is a rather awkward two-sylable construct (as are "a.m." and "p.m."!). Perhaps "19 hours 59" (or even "19 and 59") would become acceptable if someone started using it prominently?
So I would perhaps reduce the claim slightly to "In English pronounciation, there is no well-established convention to disambiguate a 24-hour time from other 4-digit numbers, such as years." Markus Kuhn 13:41, 16 February 2007 (UTC)
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