I can never remember if AM is After Midnight or After Midday or PM is Post Meridian or Post Midnight, or it's something like that, not to mention when 12:00 is... is it 12:00 or 0:00?. But ah well, I'm lucky to be in a place where we use 24h clocks (but hey, max we see is 23:59:59!) (unless they have arms). Btw, the iOS calendar is (was probably) also pretty "broken" [0]

[0]: https://www.youtube.com/watch?v=ER1a6jgW1Gs

▲ madaxe_again 5 days ago | parent | next [-]

AM is ante meridian - PM post meridian. Meridian is midday.

▲ godelski 5 days ago | parent | next [-]

Another way to remember is that A is before P alphabetically. Probably easier to remember if you don't need the other concepts

▲ 01HNNWZ0MV43FF 5 days ago | parent | prev [-]

But midnight is exactly 12 hours post and ante meridian. And meridian is neither 12 hours post nor ante of itself.

Where I can, I just say "noon" and "midnight". 12-hour time is frustrating because of this 0 == 12 bullshit

▲ exidy 5 days ago | parent | next [-]

This is the problem with the digital world. Time is analogue and continuous, digital clocks are just a quantised approximation.

Midday and midnight are points in time that have no duration -- as soon as they are observed they are passed, so midnight is 12am and midday is 12pm.

This is easier to visualise on an analogue clock with a continuous seconds hand. Although the hand sweeps past 12 it spends no time there.

Alternatively think of a digital clock with very high precision. While your ordinary clock will show 12:00pm at midday for a full minute, your high precision clock might be showing 12:00:00.0000001 -- indisputably "post meridiem".

▲ bubblebobble99 5 days ago | parent | prev [-]

That’s the point though. They are called noon/midday and midnight. There is no am/pm on the 12. It’s 11:59pm, midnight, 12:01am, and 11:59am, midday, 12:01pm. Really it’s not that confusing, it’s just two points in time in the whole day and it’s fairly easily to tell which of them you are at unless you are close to the poles.we’ve managed to cope this long with them.

	▲	exidy 5 days ago \| parent \| next [-]
		This isn't right. Midday / midnight are not the 60 seconds it takes for a digital clock to go from showing 12:00 to 12:01. They are the infinitesimally small point in time that mark the transition between "before" and "after". Like throwing a ball up into air, there is no time where it is not either rising or falling, but there is a point where it transitions from one to the other. So midday is 12:00pm. As soon as the moment has been observed it has passed, and you are now "post meridiem".
	▲	dimava 5 days ago \| parent \| prev \| next [-]
		Except 12:01 is in 24-hour clock which doesn't have 12:00 problem in the first place
	▲	godelski 5 days ago \| parent \| prev \| next [-]
		`> There is no am/pm on the 12.` This is 100% false. What are you even talking about? It's so obviously false too `> it’s fairly easily to tell which of them you are at unless you are close to the poles` How does looking out the window help set an alarm? `> we’ve managed to cope this long with them.` Look, I'm American too and I get AM/PM but lots of the world uses 24hr clocks. Maybe if you stop talking about how smart you are you'll actually be able to hear the question you're trying to answer. It'll go a long way to making other people think you're smart.
	▲	zoover2020 5 days ago \| parent \| prev [-]
		That's a lot of mental gymnastics to say 24h clock is easier

▲ ThePowerOfFuet 4 days ago | parent | prev | next [-]

PM is noon and beyond. AM resumes at midnight.

▲ hopelite 5 days ago | parent | prev [-]

You almost had me all confused with that much confused and wrong information.

It’s really not difficult, or are you doing that juvenile bit where derision masks the incompetence you admitted to?

Just remember A comes before P.

But on a related note, do you tell people you will meet at 16 or 22 o’clock? I guess if you speak some other language that strongly types time with “…Uhr”, “…Uur”, “kl.…” it makes sense that you might not notice a difference. We can just say 4 or 10 and no one is confused, based on context, that it does not mean in the middle of the night or next morning, unless of course it’s a morning related context.

It’s simply far more human oriented, just like the US Customary Measurement system is a human scale system because it was devised by humans for practical reasons and purposes, to work quickly and efficiently, not necessarily to a nanometer precision. The different systems can exist at the same time, your zealous mindset notwithstanding.

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gield 5 days ago | parent | next [-]

I'm in a country that uses the 24 hour clock. We also say we meet at 4 or at 10, and are able to derive from context whether that means in the evening or in the morning.

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radicality 4 days ago | parent | next [-]

In Poland we’ll most often use the 24hr time even when casually speaking and setting up meeting times, or people talking on tv/radio etc. Imo much simpler and less confusing

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hopelite 5 days ago | parent | prev [-]

Then you don't use the 24 time? What are you even saying. America uses the 24 time too, but it's a large country with many different nations and cultures among it that all do various different things, but I don't get all presumptions and condescending about it like the zealots that demand everyone use metric and 24 hour time and then don't even practice what they preach.

	▲	teekert 4 days ago \| parent \| next [-]
		Indeed in speech people use the 12 hr clock here (Netherlands), and you know that nobody wants to meet at 4 in the morning, so people (at least I) translate to 16:00... We have Dinner at 6, not 18:00 (people would be frowning if you'd say 18:00 out loud there). In messages I think I'm one of the few that always says "16:15" because I just hate ambiguity. If context does not clarify enough people say "in the morning/afternoon/evening/night But (easily) arguably "context" is even worse than AM/PM! Though I can't remember this going wrong ever. I remember as a kid looking at a digital clock and subtracting 2, then dropping the leading 1 to get a "feel" for the time. Nowadays I'm 24h native and don't like the ambiguity of 12 hr references. I set al my clocks to 24 hr (unless they have arms). So yeah, here we are, all cool with our "military time", ahum.
	▲	nickserv 4 days ago \| parent \| prev [-]
		That's because everyone should be using decimal time, clearly the superior representation. https://en.wikipedia.org/wiki/Decimal_time

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justinrubek 4 days ago | parent | prev | next [-]

If there's a zealous mindset here, I see it coming from this comment.

It's significantly easier to use a 24-hour clock and get rid of AM and PM. In fact, it's so easy to use 24 hours that I use it exclusively for my internal time, and I do commonly get confused by times like 12AM - is it day or night? It has a 12 instead of a 0, somewhat confusing.

I also refuse that the metric system is more difficult for human scale measurements. Ever since I switched, I have had a stronger fundamental connection to the units, and I can visualize the world better. It's significantly easier, and I would call it MORE human oriented.

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Yizahi 5 days ago | parent | prev [-]

Sequence starting at 12, 01, 02, 03 etc. is "human oriented"?

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hopelite 5 days ago | parent [-]

What do leading zeros have to do with whether people use 12 hour time instead of 24 hour time?

Why is this stuff challenging, it feels like reddit over here. My point is that saying "we will meet at 4" is more human scale than "we will meet at 16" because it segments the context window into morning and afternoon for which most humans and situations do not require additional external context to put meaning to.

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Yizahi 4 days ago | parent | next [-]

Leading zeroes have obviously nothing to do with my question. Reordered integers did though.

You'd be surprised but people in Europe also don't say "sixteen o'clock", they say "four" or "seven in the evening" if it is ambiguous. But at the same time the physical clocks and texts between people have completely clear and unambiguous time, one can understand it instantly. Why with British/USA time, when the clock is between 12 and 1, I always need to stop and analyze which of the bullshit time segments it is referencing, because of the wrong order of numbers, starting at 12, then going back to 1, then forward to 2 etc.

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roryirvine 4 days ago | parent | prev [-]

In the UK, it's pretty normal to say "oh two twenty-three" for 0223 or "fourteen thirty-five" for 1435.

But when being less precise, we might say any of "half two this afternoon", "two thirty pm", or "fourteen thirty" depending on context.

As we do still use the 12 hour clock in less-formal situations, using an "oh" prefix for times before 1000 gives an extra point of disambiguation.

	▲	nickserv 4 days ago \| parent [-]
		Interesting that you say the 'o' to explicitly indicate the 24h format. In France we just say "let's meet tomorrow at 8 hours" for example, to which the person has to ask something like "Wait, do you mean at 8 hours or 20 hours?" It's usually obvious from the context, but not always.