So if it is 13:00 on 5/4/06
…anybody in Germany, and most of Europe, can tell you it is 1:00 PM on April 5, 2006.
However, most Americans would say your clock is broken as it is impossible to have 13 o’clock, but they would let you know the date is May 4, 2006.
So with something as simple as time and date, why isn’t there a single, universal norm?
Because there’s little need.
How many Americans would really think that 13:00 was a typo? Granted, there’s potential for confusion with date shorthand, but I’ve yet to hear of anything other than minor problems having resulted from it.
How often do you see “13:00 5/4/06”? Common courtesy includes giving the day of the week of such future dates. If you’re not in the position for common courtesy, you’re in a position where everyone should know what date format is in use.
There is. It’s just that Europeans are to hard headed to accept it. 
I myself prefer to use the 24 hour clock versus the 12 hour clock. I also write my dates differently and that throws a lot of people off. Example, today is 20JUN05. Just a habit I picked up while in the Army.
Mexico does the date thing, as well. But I don’t like the 13:00 hours stuff because I’m slow at doing math in my head. And I have too many clocks to change over.
I don’t agree. The m/d/y vs. d/m/y thing can cause major headaches. If you see “5/4/06” and you know it’s American, it’s not a problem. But if there’s any doubt that it could be American, could be European, you’re either hosed, or you have to track down its origin.
As to why, you have to understand that, believe it or not, there was a time, many many years ago, when “global communication” didn’t exist. No, I don’t mean just back before there was an Internet, I mean even further back. Before long-distance phones. Before radio, even. Back to when, to get a message from one place to another, some person had to actually physically travel the distance. And back even before that. Way back then, different areas of the world developed independently and just developed different customs, that’s all. Americans all grew up with their m/d/y, and we all know how impossible it is to get Americans to change anything unless there’s clear self-interest in it. And Europeans, why should they change just to match those silly Americans, especially since d/m/y makes so much more sense?
So we live with the differences.
Well why should we? I mean, what’s in it for me?
I do the same thing Amp does, and for the same reason. Numerical day, month spelled out or abbreviated, year. Saves all sorts of confusion. Otherwise…what Ashesx2 said. 
Well, I for one would be totally confused most of the time after noon. I just can’t get used to it.
It’s like the date books that start with Monday as the first day of the week. For me it has always been Sunday. When I had a date book like that I put things on the wrong dates all the time. It was a mess.
I am just too slow/stupid for it. Also centigrade or metric. How dumb can you be that you can’t do metric? I can’t do it.
Today the custodian came into my office and wanted to know how many milliliters were in a liter. I finally got her to get out of my office and leave me alone. Why would I know the answer to that? A thousand? A million? I have no idea and I don’t care! I can’t even remember how many cups are in a gallon or how many quarts are in a gallon, etc. All I know is that I need a container that will hold four quarts and I CAN’T FIND ONE ANYWHERE! This is for some delicious lemonade. You would think when it says “add three quarts water” that a three-quart container would do, but of course that is after adding all the lemon, lime and orange juices from five fruits each, and the sugar.
And what about that song, “A bushel and a peck, a bushel and a peck, a bushel and a peck and a hug around the neck”? What did that ever mean, anyway?
Why would there be a universal norm? There is no universal language, currency, system of measurement, and lots of other “simple” things we use in daily life.
Even time and date isn’t so simple. Why is it DD/MM/YY when you yourself call it “April 5, 2006” (MONTH/D/YYYY) when you use it in a sentence? Some countries even use YY/DD/MM. Other times, people are just referring to a month like MM/YY (January of '06) and the date is excluded altogether, but there’s no way to know that by just looking at it. And spelling out the month doesn’t always work either. “January” is understood by Americans and some Europeans, but the rest of the world might not know what it is.
As for time… Swatch once tried to introduce a universal time system called Internet Time, measured in “beats” instead of seconds. 12 noon might be @750, for example. The system never caught on, obviously. Like with most other competing standards, people are just too used to their old ways.
Forget the old American and European conventions. In this computer age, we should all be using a date/time format which, if sorted as text, will be in chronological order. And it shouldn’t have a Y3K problem or a Y2.1K problem. That means YYYY/MM/DD hh:mm, padded with zeros where necessary. OP’s example would be 2006/04/05 13:00. This is also the most logical, as it goes from most significant to least significant digit. And it’s unambiguous because the 4 digit number is clearly the year, and you wouldn’t mistake it with YYYY/DD/MM because nobody uses that format.
I am a radio producer. Our clocks are 24-hour time. Non-radio people come into the station twice a year to go on the air for a certain number of minutes. There is hardly a person who has any idea what the clock means when it says 17:34:22; it just makes their brains explode when I tell them to be in at one time and out at another. We had to install a sweep clock in that studio so they could tell the time. I don’t get what’s so hard about it, but confronted with 24-hour clocks, other most of the people in my experience lose the ability to count. It must have something to do with why the temperature is still Fahrenheit and measurements are still in pounds and gallons in this country. (Well, except that they buy a 2-litre of Coke, which they insist on spelling liter.)
How about recording archivists, who catalogue concerts like this: 68-04-21? That goes against all the other systems, but it works very well in a database. I’ve not seen that dating convention used elsewhere.
I do that too!
But why stop there? Let’s use date-time groups: it is now 211020Z JUN 05 (ie 1020Z on 21 Jun 05)
Or we could use software which can recognise a variety of numerical and textual date format, including date ranges, and sort them appropriately?
:: Currently using one such database system ::
The American system is totally screwed up. Like Amp, when I was in the US Army, I learned to write 21JUN2005 or 20050621, depending on what form I was using. The Army taught us to avoid ambiguity in communications*. If you told me to meet you at 3 o’clock and I ask if you mean 0300 and you say “yes, three o’clock”. At 1500, I’m going to kick your ass after waiting 12 hours because you can’t f*cking add or subtract 12 and say what you really mean. For dates, I’ve come to prefer yyyy/mm/dd because it sorts correctly every time.
Bingo, we have a winner. This is the date format from my mainframe days, at one time they were thinking of using different software and I managed to convince everyone that it would cost us a fortune due to the change in date format alone. As it turned out our two standard date routines (one online and one batch) were Y2K resistant simply because of us sticking to the date format. I still reap the benefits.
We could in most cases, but it’s still nice to be able to sort as text. For example, I always name data files and digital camera image files as YYYY-MM-DD-hh-mm-ss or some variant of it. That way, even if the time stamp of the file gets changed (by editing or copying the file), I can sort the files by name and they’d be in chronological order.
And as I said, there’s no way for a software (or a human) to distinguish between MM/DD/YYYY and DD/MM/YYYY by just looking at the date, whereas YYYY/MM/DD is unambiguous.
I had the same experiance when I worked in a hospital. In at 1830, out at 2230, break at 2000. It got to be second nature for me. Then one day I’m sitting watching TV with a friend of mine, not the sharpest knife in the drawer but still a college grad. The program showed time in the 24 hour format and the guy keeps asking me what time it was. He was totally amazed I could figure it out. Just subtract 12, dumbass!
That’s not too far off from ISO 8601, the international standard for date and time representations. It uses a YYYY-MM-DD HH:MM:SS format with a 24-hour clock. Very unambiguous, and very easy to sort in order.
Quick question? Who else has to fill out timesheets in decimals? 4 hours 10 minutes becomes 4.17…2 h 15m becomes 2:25. I always mess it up at least once.
Currently working for a law firm that bills only in 6 minute increments. So .4 is 24 minutes, .8 is 48 minutes and apparently it is impossible to work on something under 6 minutes.