The 2000’s began in the year 2000.
24-hour clock is officially called; " the international standard notion of time .
You frequently hear people refer to; " 8AM in the morning"
Is this to be sure that the other party don’t confuse it with; “8PM in the evening”?
Or is it because the speakers don’t know what AM and PM stands for themselves?
To make it even more confusing, the abbreviation used can be; PM, p.m., or (British) pm.
PS> As all Navigators know; AM = Ante Meridiem. PM = Post Meridiem (But who else care?)
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Don’t get me started on “feels like temperature” or “meteorological Spring”
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Or the “overnight hours” instead of overnight. They must all go to the same weatherman school but only on days when the windchill factor isn’t too bad.
That’s also where they learn the size of hail must be described in terms of fruit or sports equipment. It’s apparently an elective because neither my wife or I had that when we got our meteorology degrees.
You must not have been in the meteothespian program.
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A friend was returning from selling farm chemicals in Mexico. He had tuned into a radio station in Yuma Arizona for a weather report. They said the high temperature would be 121 degrees… with the wind chill though they should only feel like 119.
I’m sensing a chill in the air, Be especially attentive to the GUSTS !! Buy extra water,batteries,blankets. BR-R-R… Job Justification. By the way in Canada most people use the AM PM method, except for Mariners and the Military.
Being facetious when first asking, 
I knew I’d regret asking this…
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The am/pm system became less useful when sundials were replaced with clocks and should have been abandoned.
But it wasn’t, so the question arises if midnight has to be labeled using am or pm which is more intuitive and/or useful?
Midnight is both the end and the beginning of the day of course but the fact that the convention is to label midnight as a.m. implies that for the purpose of labeling it’s thought of as the beginning of the day.
Evidently that same intuition manifests today in the ISO 8601-1:2019 standard.
With the introduction of Time Zones any use of the sun’s meridian passage as reference for AM/PM is pointless. With the introduction of Daylight Saving Time it becomes even more so.
As a example:
Here in Ålesund, (at 6.5E Long.) the Time Zone should have been GMT (Zulu) but we follow the rest of NW Europe and use CET (Z+1)
During summers the change to DST puts us at EET (Z+2), which means that True Noon is at abt. 13:20 hrs. (Actual “Midnight” at abt. 01:20hrs.)
Does that mean that 13:00 hrs. should be called 13AM, since it is before “Noon” by the sundial?
ITC: is 01:00 hrs. (13 PM) actually today or tomorrow?)
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Not using LAN or LMT as a reference. Today AM/PM means before/after noon by the clock.
The role of the sundial is that it’s use led to the adoption of the 12-hour day. The day was divided in half, day and night and the day divided into 12 hours.
When mechanical time pieces were adopted the day was divided into 24 hours. In that case the 24-hour clock resolves the am/pm ambiguity and makes more sense.
Here’s a stack exchange thread wrt this problem.
Just read some more on the thread above, it’s a good one and does support the midnight should be pm which is argued in the OP.
From the substack post above,
What you see with “11 ᴀᴍ + 1 hour == 12:00 ᴘᴍ” is largely an artifact of the way we keep time with a zero-based system on computers per ISO 8601, and what happens when you map a zero-based 24-hour time like 00:00:00.00000 into a 12-hour ᴀᴍ/ᴘᴍ time, which is one-based.
In short, for quite a very long time (up to 2008 for at least one important U.S. government agency), it used to be that 11 ᴀᴍ and an hour was still considered 12 ᴀᴍ, even though a minute after that it became ᴘᴍ. In the same fashion, an hour after 11 ᴘᴍ was once considered 12 ᴘᴍ, and some people still interpret it that way, although computers are (now) required not to do so.
The hours of the calendar day used to work this way:
- ᴀᴍ: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
- ᴘᴍ: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
That way everything made sense because an hour after eleven in the morning was still twelve in the morning, and an hour after eleven at night was still twelve at night.
But now with a zero-based system being used by computers, mapping that to the traditional English system yields the awkward progression:
- ᴀᴍ: 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
- ᴘᴍ: 12. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
This is unfortunate, and surprising as you notice. And not everyone does it that way, even though computers do.
That there is no consensus here about noon and midnight is the real problem. This notation has various issues and ambiguities because exactly noon is neither before noon nor after it. A similar problem exists for midnight. You are advised not to ever write ᴀᴍ or ᴘᴍ in conjunction with 12 o’clock because different people interpret noon and midnight differently.
How did this happen? That’s a longer story. Here’s part of it.
(longer story continues at the link)
Yes I know how it is USED and what it ACTUALLY means. I thought that was quite clear from my post. (??)
BTW; Noon means the time of the sun’s meridian passage, no matter what your clock shows, but is commonly used to describe 12:00 hrs. by the clock. (Whether that should be described as 12AM or 12PM was actually the OP’s question IIRC)
An anecdote:
In my young and tender days I sailed with an old Master that insisted that while on ocean crossings ship’s time should be adjusted nightly to True Time next Noon.
(I.e. to make the sun’s meridian passage at 12 Noon, or as close to it as possible)
He himself and all tree Mates were on the bridge to catch the meridian passage and calculate Noon Position.
PS> For some reason his position was always the one entered in the Log Book.
Yes that is what I said, so we appears to agree:
PS> “Solare noon” = Noon by the sun’s meridian passage.
SO, to go back to my original question , it seems I used to be right. But time and computers have passed me by.(as have many customs). I use noon and Midnight anyway, to avoid any confusion.So I will continue to be right even if people don’t understand, and I will watch the world go by in my blissful supposed ignorance
Thanks everybody, this has been quite educational, and no timeouts!!
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I think you’re still right. I thought naming midnight was a six of one and half a dozen of the other but now I think strictly by logic the stronger case is for midnight being pm.
It’s a redundant saying. Another example: RHIB boat.
Some funny ones listed here.
- Plan ahead: To plan is to prepare for the future. Ahead is extraneous.
- Suddenly exploded: An explosion is an immediate event. It cannot be any more sudden than it is.
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Indeed, it has been entertaining watching people get wound up over time [puns intended]
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