Because for all it's flaws it was entrenched thorughly, and is used for navigation before metric was invented. Latitude and Longitude aren't metric either, but they're not likely to change. Metric has advantages, but they are not so overwhelming that it can force the USA to change (yet). Any system that is consistance works well enough.
Both systems are completely arbitrary. There is no "inherent" truth in either system. The metric system has wider acceptance and is more popular. Now, not to start any arguments... Don't forget that in the English/Imperial system we have a dimension called the mil for which there is no simple metric equivalent. And the English system is quite comfortable using fractional values and decimal values. The metric system is not. I can't find any store that will sell me 1/3 meter of cloth. Personally, I think suits made to the English system fit better too. John
There was metric time, back in Napoleon's day. Months, weeks, hours, and minutes were all adjusted to have decimal values.
The units for time, as well as angle measurement, come from the Babylonians or 3000 or so years ago. As you know, there are 60 seconds in a minute (time and angle measure), and 60 minutes in an hour or degee. A full circle is made up of 360 degrees. All of these numbers are multiples of 20, which is perhaps not coincidentally the number of fingers and toes most of us have. 60 is a useful and convenient number system base, since it is divisible by 2, 3, 4, 5, 6, 10, 12, 15, 20, and 30 (and of course, 1 and 60). If you have 60 things and want to divide them into n groups with n being one of the numbers I listed, you can do so without having to resort to fractions. On the other hand, if you have 7 things, you can't divide them among 2, 3, 4, 5, or 6 groups without resorting to fractions, a concept that didn't come along until long after the Babylonians.
I'm confused. Doesn't the metric system just use seconds as the unit of time. Or perhaps I'm confusing SI and CGS units with metric. I guess there would be a distinction. We use seconds in a "metric way" all the time in science and engineering. We have milliseconds, microseconds, nanoseconds, picoseconds etc. Nothing stops us from going the other way: that is, kiloseconds and gigaseconds. It's just that nobody finds it convenient to use these longer time units since minutes and hours are already established, and days, months and years have observable meanings based on astronomy. An interesting question might be. If one were free to choose any time unit for the metric system, what would be better than the second? Is there any unit that would produce convenient numbers for the length of a day, month and year simultaneously? Off topic a little: I've always been annoyed that we do not have 13 months in a year. Did you every notice that 365/13=28.08 days and the length of a lunar month is in the 27.3 to 29.6 day range depending on how you define the lunar circuit (sidereal, synodic, anomalistic, tropical, draconic)? It would be a much nicer if every month were 28 days since all months would be the same length and would equal 4 weeks exactly.
A 13-month calender would make it more complicated for reporting quarterly profits or losses. It's hard enough to come up with tax payments quarterly as well. I would hate to have to do that every month. John
One would just use a weekly breakdown for quarters. Every 13 weeks is a quarter. Hey, 13 showed up again. Works fine unless you are superstitious. Seriously, I do this whenever I do project planning. I might do a general plan in terms of months, but any detailed plan always is organized in weeks. It wouldn't take long to know the dates of a quarter. 1/1, 4/8, 7/15, 10/22 then party on 13/28 at midnight.