Americanisms like "noon" or "4 p.m."

Huh. I had never thought of these as Americanisms (though being from the States I might say that, right?) I've lived abroad in a country that uses a 24-hour clock for more official uses, and 12-hour clocks for more informal, spoken uses, including the use of the concept of "noon".

Given my small sample size, I looked at Wikipedia to see how time is referenced in other countries. I was surprised to see that the first five countries I looked at all have mixed usage of 24-hour and 12-hour (except for Thailand, which has a 6-hour clock).

Both the 12-hour and 24-hour notations are used in the United Kingdom. The 12-hour notation is still widely used in ordinary life, written communication and displays, and continues to be used in spoken language.

https://en.wikipedia.org/wiki/Date_and_time_notation_in_the_...

Turkey uses the 24-hour clock system. In informal speech, however, the 12-hour clock is more commonly used. When speaking in the 12-hour system, the words such as "sabah" (morning), "akşam" (evening) or "gece" (night) are generally used before telling the time to clarify whether it is a.m. or p.m.

https://en.wikipedia.org/wiki/Date_and_time_notation_in_Turk...

In Thailand, official time is indicated in 24-hour clock system; however, a six-hour clock system is also used, especially in spoken language. It divides the day into four six-hour periods, with additional words added to make the night-morning-afternoon-evening distinction.

https://en.wikipedia.org/wiki/Date_and_time_notation_in_Thai...

In spoken Swedish however, the 12-hour clock is much more common.

https://en.wikipedia.org/wiki/Date_and_time_notation_in_Swed...

In common spoken language, times are given in 12-hour clock, and those between 1 and 11 are assumed to be post meridiem, past noon, if not otherwise noted.

https://en.wikipedia.org/wiki/Date_and_time_notation_in_Spai...

I haven't done an exhaustive search through the rest, but this does strongly suggest that these are not only Americanisms. If I'm missing something, or misinterpreting what you're saying (which wouldn't be the first time :) please let me know and clarify.

As for the numbers being arbitrary, I agree. There is a utility to the choice of 24 hours in a day. That doesn't get around the behavior of humans, where our own biology follows the sun. We'll for the most part be awake when the sun is up, likely be active in community during the middle of the day, at home in the morning and evening. In a global world, we need some way to coordinate with people living at different longitudes, especially for synchronous tasks. Is there a significant difference between needing to know that working hours is from 9:00 and 17:00 in London and from 4:00 and 12:00 in New York, and looking up the time difference between London and New York is 5 hours? Six of one, half-dozen of the other, seems to me.

We'll still need some way general convention locally as well. It'd be interesting to see what the business hours are (at a per-business level, perhaps) in relation to the time zone and nearness to time zone borders, and see if there are any trends for businesses compensating based on what the time zone is for the majority of the local population. There'd still need to be some convention for locales. With a limited number of time zones, that decision and coordination is taken care of.

Maybe I'm approaching this wrong, but so far what I've read hasn't convinced me that getting rid of time zones does anything more than shift the issue elsewhere. Given that it makes sense to some people, I'm open to hearing more. While I might not agree with some opinions, I generally want to be able to understand how people come to them. Thanks for reading!