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12am/12pm are ambiguous and should be avoided when possible. Try asking people what time 12pm means and you'll see that some will struggle and some will get it

12am/12pm are ambiguous and should be avoided when possible. Try asking people what time 12pm means and you'll see that some will struggle and some will get it wrong, especially if they're from a place that uses a 24 hour clock. But even a 24 hour clock is ambiguous at 00:00. What date should it be? This can be solved by using 11:59 and 23:59 instead. 12pm is usually used for noon. Ironically, of the two choices, it makes the least sense. It makes the PM hours become: 12, 1, 2, 3... When one would expect: ...9, 10, 11, 12 Unfortunately, people weren't quite as into zero-indexing in ancient history.

scrollaway 8y ago
Right, 12 is 0 on AM/PM clocks. Once you get to understand that, it's easy to reason with (though 24-hour clocks are the far superior siege weapon). 00:00 is not ambiguous, though. There is no such date on 12-hour clocks (there's no zero! Just 12…), and on 24-hour clocks it's unambiguously the beginning of the day (24-hour clocks are zero-indexed). In fact, 00:* dates are consistently unambiguous, because they don't require you to define whether you're using a 12 or 24 hour clock. I think you're thinking about 12:00 on 12 hour clocks.