I think almost everybody in European countries knows about AM/PM, but I certainly get confused by 11:59 AM vs 12:00 AM
In Polish it's 8 rano (in the morning) vs 8 wieczorem (in the evening).
I can't remember which is which in AM/PM, and have to check each time :)
And the issues with midnight/noon are frustrating and 12-hour-clock should just die.
I assume some people (perhaps older people) wear analog 12h wrist watches, and wouldn't translate to 24h after looking at it to answer a random question "what time is it?"
Now I almost never hear "6 wieczorem" it's always 18. I think I haven't heard it used this year in Polish.
Lots of people use analog clocks but they just say 18 when looking at 6.
In my experience in Finland, casual spoken discussion is usually 12h but written is 24h. The xx:xx format always means 24h, whether written or spoken.
When referring to a precise minute 24h is common even when spoken - "train leaves at sixteen thirty-four" - the 12h alternative is "train leaves at four past half five" or "twenty-six to five". Notably, one would never say "four thirty-four" as that refers to 04:34 (24h).
Also, 12h is used when casually written with letters - e.g. it would be "meet you at three" / "nähdään kolmelta", not "meet you at fifteen" / "nähdään viideltätoista".
My exact experience in France as well. “Six heure du matin” for example.
Is there a mnemonic or trick for remembering?
Apres midi Post midi
But surely the whole point is that midday itself is neither before nor after midday, while midnight is precisely equally both before and after?
I try always to use 12 noon and 12 midnight instead.
What if a plane crashes on my house, between policies, during those two uninsured minutes?
Sure, it's unlikely, but so are all the other things that might cause me to claim on my buildings insurance policy.
The other fact that helps me remember is that 12 hour clocks were invented before the number 0, and afterwards 24h clocks are 0-based, so 12 on an old clock is the start of the am or pm cycle respectively because there is no 0. Really 12 should be 0 and then it all makes sense.
12PM is morning, 12AM is afternoon.
Again, as a Polish person I don't think that's true at all, certainly in Poland it isn't.