Technically it’s morning. Not even an argument. My answer was purely based on the clock system. But I think the answer is actually a bit more complex depending on your location and time of year. After reading the definitions of Morning, Night, Day, Midnight, and AM/PM, my answer is that 12 AM can be Morning, Morning and Night, or Morning and Day. I do not believe 12 AM can solely be called Night based on the phrasing of your question. It seems like your uncle is conflating Afternoon (PM) and Night (period of time from sunset to sunrise). By definition 12 AM is the start of the morning hours or Ante Meridian. So by the clock system it’s Morning. The definition of Night is the period of time from sunset to sunrise. In many parts of the world during much of the year the sun has set when the clock strikes 12AM. Thus 12 AM is by definition both Night (no sunlight) and Morning (AM). There are parts of the world (think extreme North or extreme South) where the sun does not set for months. In these parts of the world, during these seasons of seemingly unending daylight, 12 AM is both Morning and Day. As Day is defined by the period of time from sunrise to sunset. If you really wanted to split hairs the final scenario that I can think of, is where 12 AM is simultaneously Midnight, Morning, and Night or Midnight, Morning, and Day. Depending on location, season, and the presence or absence of sunlight and the definition of midnight. Just don’t ask if 12 PM is considered Afternoon or Day. Answer from ScottyJobs on reddit.com
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NPL
npl.co.uk › resources › q-a › is-midnight-12am-or-12pm
Midnight - is it 12am or 12pm? - NPL
There are no official standards established for the meaning of 12am and 12pm, but it is generally accepted that 12am means midnight and 12pm means midday. The ‘am’ and ‘pm’ stand for ante meridiem and post meridiem – Latin words meaning ...
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Royal Museums Greenwich
rmg.co.uk › stories › time › noon-12-am-or-12-pm
Is noon 12 am or 12 pm? | Royal Museums Greenwich
When they say 12am, they normally mean 12 midnight. While some people follow this convention, technically it's not quite right – as you'll see from the definition of am and pm below.
Discussions

If 12 AM is midnight, why is 12 PM noon? Shouldn’t “AM” stand for after midnight and “PM” after morning?
AM stands for "ante meridiem", which means "before midday" and PM stands for "post meridiem", meaning "after midday." More on reddit.com
🌐 r/NoStupidQuestions
5
0
May 20, 2025
Is 12:00 AM considered morning or night?
Technically it’s morning. Not even an argument. My answer was purely based on the clock system. But I think the answer is actually a bit more complex depending on your location and time of year. After reading the definitions of Morning, Night, Day, Midnight, and AM/PM, my answer is that 12 AM can be Morning, Morning and Night, or Morning and Day. I do not believe 12 AM can solely be called Night based on the phrasing of your question. It seems like your uncle is conflating Afternoon (PM) and Night (period of time from sunset to sunrise). By definition 12 AM is the start of the morning hours or Ante Meridian. So by the clock system it’s Morning. The definition of Night is the period of time from sunset to sunrise. In many parts of the world during much of the year the sun has set when the clock strikes 12AM. Thus 12 AM is by definition both Night (no sunlight) and Morning (AM). There are parts of the world (think extreme North or extreme South) where the sun does not set for months. In these parts of the world, during these seasons of seemingly unending daylight, 12 AM is both Morning and Day. As Day is defined by the period of time from sunrise to sunset. If you really wanted to split hairs the final scenario that I can think of, is where 12 AM is simultaneously Midnight, Morning, and Night or Midnight, Morning, and Day. Depending on location, season, and the presence or absence of sunlight and the definition of midnight. Just don’t ask if 12 PM is considered Afternoon or Day. More on reddit.com
🌐 r/NoStupidQuestions
16
4
March 20, 2020
Is 12 PM at noon? How is that when 11 am is in the morning And 1 am is in the night. Where did the 12 am go?
12pm is noon, 12am is midnight. More on reddit.com
🌐 r/EnglishLearning
156
96
August 22, 2024
time - Is it correct to say "12:00am"? - English Language & Usage Stack Exchange
In my opinion, it is more ambiguous to say "12:00 midnight Tuesday" than to say "12:00am Tuesday"- 12:00 midnight Tuesday could be construed to be at the end of Tuesday, while 12:00am always means at the beginning. More on english.stackexchange.com
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EnglishClub
englishclub.com › efl › articles › vocabulary › 12am-12pm-whats-the-difference
12am & 12pm – What’s the Difference?! | EnglishClub
Where the problem always arises is when you go to make a reservation online and it asks 2; AM or 12:00PM, so of the minute before noon is 11:59 AM, Then noon must be 12:00 PM ... In case of doubt I recommend always to use the 24-hour clock, which means writing the time with four digits, like: 01.20 (The leading zero indicates that this is the 24-hour clock and must mean 1.20am in the morning.
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Wikipedia
en.wikipedia.org › wiki › 12-hour_clock
12-hour clock - Wikipedia
1 week ago - The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin ante meridiem, translating to "before midday") and p.m. (from Latin post meridiem, translating to "after midday"). Each period consists of 12 hours numbered: 12 (acting as ...
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TimeAndDate
timeanddate.com › time zones › am and pm
AM and PM: What Do They Mean?
The 12-hour system divides the 24 hours of a day into two periods lasting 12 hours each. Noon serves as the dividing point between the two periods and as the basis for the designations am and pm: ... AM means before noon.
Find elsewhere
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Quora
quora.com › What-is-12-am-and-12-pm
What is 12 am and 12 pm.? - Quora
To me, it is very clear that 12 am is midnight, and 12 pm is noon. 12 am is the instant the day changes.
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Reddit
reddit.com › r/nostupidquestions › is 12:00 am considered morning or night?
r/NoStupidQuestions on Reddit: Is 12:00 AM considered morning or night?
March 20, 2020 -

My uncle and I are arguing about whether 12 AM is considered morning or night. I'm not going to say which side I take so I don't skew the results. Hopefully y'all can solve this argument.

Top answer
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Technically it’s morning. Not even an argument. My answer was purely based on the clock system. But I think the answer is actually a bit more complex depending on your location and time of year. After reading the definitions of Morning, Night, Day, Midnight, and AM/PM, my answer is that 12 AM can be Morning, Morning and Night, or Morning and Day. I do not believe 12 AM can solely be called Night based on the phrasing of your question. It seems like your uncle is conflating Afternoon (PM) and Night (period of time from sunset to sunrise). By definition 12 AM is the start of the morning hours or Ante Meridian. So by the clock system it’s Morning. The definition of Night is the period of time from sunset to sunrise. In many parts of the world during much of the year the sun has set when the clock strikes 12AM. Thus 12 AM is by definition both Night (no sunlight) and Morning (AM). There are parts of the world (think extreme North or extreme South) where the sun does not set for months. In these parts of the world, during these seasons of seemingly unending daylight, 12 AM is both Morning and Day. As Day is defined by the period of time from sunrise to sunset. If you really wanted to split hairs the final scenario that I can think of, is where 12 AM is simultaneously Midnight, Morning, and Night or Midnight, Morning, and Day. Depending on location, season, and the presence or absence of sunlight and the definition of midnight. Just don’t ask if 12 PM is considered Afternoon or Day.
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Is both an option?
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Medium
medium.com › @CelineL › is-12-midnight-a-m-or-p-m-44de05ad46e7
Is 12 Midnight A.M. or P.M?. Maybe we need new acronyms for midday… | by Grace Mary Power | Medium
November 24, 2025 - I used to ask myself “Is midnight 12 am or 12 pm?” · My research has shown that there are no official standards established for the meaning of 12am and 12pm, but it is generally accepted that 12am means midnight and 12pm means midday.
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The Wikipedia article 12 Hour Clock is worth quoting at length:

Confusion at noon and midnight

It is not always clear what times "12:00 a.m." and "12:00 p.m." denote. From the Latin words meridies (midday), ante (before) and post (after), the term ante meridiem (a.m.) means before midday and post meridiem (p.m.) means after midday. Since strictly speaking "noon" (midday) is neither before or after itself, the terms a.m. and p.m. do not apply. However, since 12:01 p.m. is after noon, it is common to extend this usage for 12:00 p.m. to denote noon. That leaves 12:00 a.m. to be used for midnight at the beginning of the day, continuing to 12.01 a.m. that same day.

However, because practical confusion is still possible, some style guides recommend replacing "12:00 p.m." with "12:00 noon" and "12:00 a.m." with "12:00 midnight".

The American Heritage Dictionary of the English Language (Fourth Edition, 2000) has a usage note on this topic: "Strictly speaking, 12 a.m. denotes midnight, and 12 p.m. denotes noon, but there is sufficient confusion over these uses to make it advisable to use 12 noon and 12 midnight where clarity is required."

Many U.S. style guides, and NIST's "Frequently asked questions (FAQ)" web page, recommend that it is clearest if one refers to "noon" or "12:00 noon" and "midnight" or "12:00 midnight" (rather than to "12:00 p.m." and "12:00 a.m."). Some other style guides suggest "12:00 n" for noon and "12:00 m" for midnight.

The Canadian Press Stylebook (11th Edition, 1999, page 288) says, "write noon or midnight, not 12 noon or 12 midnight." Phrases such as "12 a.m." and "12 p.m." are not mentioned at all.

The use of "12:00 midnight" or "midnight" is still problematic because it does not distinguish between the midnight at the start of a particular day and the midnight at its end. To avoid confusion and error, some U.S. style guides recommend either clarifying "midnight" with other context clues, or not referring to midnight at all. For an example of the latter method, "midnight" is replaced with "11:59 p.m." for the end of a day or "12:01 a.m." for the start of the next day. That has become common in the United States in legal contracts and for airplane, bus, or train schedules, though some schedules use other conventions.

My advice is to use "12:00 noon" instead of "12:00 p.m." and "12:00 midnight" instead of "12:00 a.m." Realize that readers may be confused which day 12:00 midnight belongs to, so make sure context makes it clear.

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12:00am is correct.
The clock goes from 12:00am (midnight) through 1:00am, 2:00am to 11:59am and then to 12:00pm (noon) through 1:00pm to 11:59pm and repeats.

It seems no more strange to go from 12:59 to 1:00 than it does to go from 11:59pm to 12:00am

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Quora
quora.com › Why-do-we-have-12-00-AM-and-12-00-PM-for-midnight-and-noon-and-what-s-the-correct-way-to-write-them
Why do we have 12:00 AM and 12:00 PM for midnight and noon, and what’s the correct way to write them? - Quora
Since time only goes forward, when you see the marker 12 AM, you know that you are stepping into the time of AM or beginning of the day. 12 PM denotes the peak of the day, and the sun begins its descent.
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Timewatch
timewatch.com › home › am pm explained. is noon 12am or 12pm? why are there 24 hours in a day?
When is 12:00AM Tuesday? AM PM Time Format Explained?
October 31, 2025 - Is it midnight on Monday, Tuesday noon, or Tuesday midnight? “It’s Tuesday morning!” you may say confidently, but is it? We asked 100 people and received three answers to this question.
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QuillBot
quillbot.com › home › is 12 am morning?
Is 12 am morning?
August 21, 2025 - 12 a.m. is midnight, the point at which one day finishes and the next day starts, so 12:01 a.m. is technically morning.
Top answer
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It's a matter of convention, and the informal convention is that "midnight on the 10th" is more commonly the night between the 10th and the 11th. But the term is awfully ambiguous, and people do use it both ways.

(When I've scheduled things with "midnight" deadlines, I always say "11:59pm on the 10th" or something like that, to avoid the ambiguity. From experience, if you don't people will ask which you mean.)

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By most definitions, the date changes at midnight. That is, at the precise stroke of 12:00:00. That time, along with 12:00:00 noon, are technically neither AM or PM because AM and PM mean "ante-meridiem" and "post-meridiem", and noon and midnight are neither ante- nor post- meridiem. However, for convenience, most people lump the 12:00:00 time with its nearest neighbour, 12:00:01, which IS AM or PM.

Since the date changes at the stroke of midnight, there is always ambiguity about which date you refer to. Midnight on the 10th technically means at the start of the 10th, but when most people speak they mean it to be at the end of the 10th.

If I said "I'll meet you Friday at midnight" or "I'll meet you Friday night at midnight" you (and most people) would probably interpret both times as the midnight that follows Friday noon. However, there are cases where the first sentence really means "the midnight at the start of Friday".

Since the common usage conflicts with the technical definition, if you want to be totally clear, use other words or other times.

Friday night at midnight

probably will always be interpreted as "Midnight in the night which follows Friday evening".

Midnight tonight

This means (to me) the midnight following today.

11:59 PM Friday

12:01 AM Saturday

These are totally unambiguous.

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WordReference
forum.wordreference.com › english only › english only
12am / 12pm - Which is noon? which is midnight? | WordReference Forums
June 27, 2012 - ... There appears to be a convention that 12am is midnight, 12pm is noon - but that is not universal, else we wouldn't be having this discussion for at least the fourth time in WR Forums.
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Reddit
reddit.com › r/englishlearning › 12.00am means midnight?
12.00am means midnight? : r/EnglishLearning
March 20, 2025 - However: AM means ante meridiem ("before midday" in Latin) and PM means post meridiem ("after midday"). 12:00 of course is midday, so it doesn't really make sense for it to be AM or PM; however, as soon as we're past 12:00 (for example, 12:01) we are after midday, or "post meridiem" (PM).
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Quora
quora.com › Is-noon-12AM-or-12PM
Is noon 12AM or 12PM? - Quora
There, the beginning of the day (12 am or 12 midnight) is denoted by 0000 hours, and ends a ... Noon and midnight are instances where logically the am and pm do not abide by what they mean, i.e.