Why do Americans want to know the month first and the day second?

Year is the most significant (read: big) unit in the list, but it is the least significant (pertinent to daily life) unless you're a time traveler. Of month and day, month is more significant than day in both size and pertinence, so it gets ordered first. But when sorting things into folders or file naming conventions, biggest category descending down to smaller categories is always the best.
- You articulated what I was thinking, better than I could have. This is it for me.
  I'd add that there's probably a lot of habit involved, plus the fact that everyone else does it.
  So not only am I not used to saying "today is the 4th of May", everyone around me isn't used to hearing it either and might think I'm being weird.

Ignoring the coding side of things...
It's relative. And also works easier to navigate the calendar. If we're planning something for next year I pull up next year's calendar. If it's this years and we're planning something for later this year, when I hear you say August, that's the month I go to. But if you say the 27th of August, The first thing I heard was the 27th which could possibly be this month or next month if it's say the 28th today.

American here. No idea. Either DD/MM/YYYY or YYYY/MM/DD are more logical, but here we are. When naming/renaming files and including a date in the name, I'll usually do YYYYMMDD format somewhere. If I'm emailing/texting others, I use MM/DD/YYYY.
Fun little story, the department I work in recently began to work with some people over in the UK, and even though I brought up the date format differences, we've already had someone of gett the month and day flipped and it caused some confusion on our end.

Most significant digits first. You write the thousands place before the hundreds, you write the month before the day. Of course, the whole argument is blow away when you write the year at the end instead of the beginning. (ISO YYYY-MM-DD dates for the win.)
- Most significant digits first.
  That would only make sense if the US wrote the year first, but they don't. They just seem to slap the date together in a random order
  
  I think that's context relevant though. If we think about when dates are most frequently used (news, business, planning) it's typically within the year (or month will give context).
  That added with the fact it's not uncommon in some situations to just provide month/day.
  That being said, I don't think either is better or worse. Just a preference kinda thing, unlike the issue between metric and imperial units.
- little Endian entered the chat.

To make sure its not December right away. Fuck that entire month. Everyone hates December so much they throw the years biggest party at the end of it.

I write the date a bit different depending on which format its going on.
For example, computers like to sort things alphabetically. If I'm writing electronic diary entries, I'll name the document as "2025-06-01."
If I'm hand signing a legal document, I prefer to sign it as "01JUN2025" or "01JUN25" if space is an issue.
If the format is preselected and deviation isn't allowed, I'll just write it like everyone else does.
Personally, I like dating things in ascending or descending order. Day month year, or year month day.
- I'm a fan of the 01JUN2025 format. It's unambiguous and uses about the same space as other traditional formats.
- Personally, I like dating things in ascending or descending order
  Hey! Me too! 🤝

As an American it was just what we were taught. However, when I started creating code and being pedantic about organizing files by date, I now prefer YYYYMMDD format as it is, chronologically speaking, superior when prefacing files with it. In this case, in my opinion, it's better to have the year and then month first prior to day.
To each their own, variety is the spice of life.
- This is the only format that truly makes sense, as it is both unambiguous and, as you noted, sortable.
- ISO is my true north.
- What you say is interesting. Having a way of organizing time that suits your needs. That's why I asked if there was any benefit in the way Americans (and apparently also Chinese) represent time.
  
  Interesting thing about how Chinese time is organized is locations are also stated big to small. Last names then first names etc.
- This. I usually use MMDDYYYY when I'm dealing with other (US) people and ISO standard for my own stuff.

Because the month is bigger and provides more context on it's own. You figure out the month first then place yourself within that scale.
Example:
"It's May (immediately tells us the context of 31days, spring, etc.) It is the 30th, so there's one day left in May"
Vs
"It's the 30th (provides no context except that it's not February). it's may, so there's one day left in May"
So both lead to the same conclusion, the first way just gives the limiting parameter/most context first.
Similar reasoning why the month is the primary separation on calendars.
Another example that follow this same principle, you tell time HH/mm to provide the larger context first, not mm/HH.
- you tell time HH/mm to provide the larger context first, not mm/HH.
  Except not everywhere does, at least in speech. Half past ten. Quarter to eight. Five past three.
  Although in the US I suppose you do say ten thirty, and seven forty-five? So at least you are consistent!
- This pretty much sums it up for me, knowing the month first conveys a lot of information. Then the specific day gives more precision, year you can often assume but it's there in case it's not what you expected.
- Surprised I had to scroll all the way to the bottom of the comments to find this answer

The short answer is, it's what we were taught in school. Like many preferences, it's shaped by the culture we grow up and live in.
I’m sorry but it doesn’t make sense to me.
Of course not, you were raised and live in a different culture; so, your preferences are different.
Ultimately, the right answer is ISO8601. It's unambiguous and sorts well on computers. But, I don't think any culture is teaching that as the primary way to write dates, so we're stuck with the crappy ways.
- There is an American subculture teaching and using ISO 8601; the US military. They don’t call it that, but I learned later that’s what it is. They enforce YYYY-MM-DD on all documents.
- YYYYMMDD is commonly used throughout East Asia.

If you name your files YEAR-MONTH-DAY_Filename they be in chronological order when sorted by the name field.
- YYYYMMDD is the only correct answer.
- That's not a good explanation for the question, because the convention was established before computers.
  
  I answered the one question he posed. What is the benefit of doing it the other way around?
  
  I mean it's easier to sort like that for humans too.
  
  My GP has cabinet with patient information.
  The drawers are years, and then inside it narrows down to months. Probably the answer.

Because the day doesn't matter when you work every day between your three jobs that won't give you 40 hours in order to not give you health insurance.
- That escalated quickly...

I can't say it matters to me that much what order it's in, but that's just the same order we say it in when fully written out. March 23, 2025. 03/23/2025.
- Maybe it's a language specific thing? In my native tongue March 23 sounds like a journal entry, not a normal date.
- Not an American. But I've heard the same explanation. And it does make sense to me.
  However, why do Americans say "Fourth of July" then?
  
  Because its a holiday
  
  For some reason doing it that way sounds extra fancy to us. At least it does to me. More formal I guess?
  
  Forth of July is a forced special case that we USians have been conditioned into differentiating. Strange shit like that due to nationalism. We don't do that for most other dates or holidays, though. Like, hardly anyone goes around routinely saying 31st of October to refer to that holiday.
  Maybe the UK equivalent would be the 5th of November. (Or was that just popularized because of V For Vendetta?)
  I suppose I've heard the Ides of March plenty, as well.

Am American and I hate the MM/DD/YY(YY) format. Unfortunately its what's been taught and used as the standard date format for a long time.
I much prefer the ISO standard of YYYY-MM-DD. It's the superior format logically moving from the largest calendar unit to the smallest. Also superior for date ordering files.
- Yeah, I resently saw it and I agree with you.

It's two less syllables to say "April Fourth" than "The Fourth of April".
That's about the only advantage it has.
Edit:
I was thinking about this grammatically. English is an Adjective first language where the modifying adjective goes before the base noun.
In my example, April is the adjective. It tells the reader what kind of Fourth it is.
It's at least a kind of logic.
- Understandable.
  
  FYI, I added more in the base comment.

ITT: defensive answers and ISO-8601 supporters.
- Yes, I didn't quite calculate how controversial the topic would be, my bad...
  
  I think the clear answer is that there is no real reason other than habit and sunk cost fallacy.
  See also the metric system, A4 paper, and daylight-saving time.

The month tells you more about conditions like weather but that's kinda it.

Probably because in english it's the way they speak about dates (and the fact US kinda isolated themselves before WWII).
They started to write dates as they speak dates.
- Sounds plausible

Why do Americans use MM/DD/YY for date, but not mm:ss:hh for time? Doesn’t that make the same amount of sense?
- I don't know! that's why I'm asking!
- Your looking at it from a digital era. When things were paper based, month-day-year made a bunch of sense.
  Our work paper archives are stored in "year" boxes (used to be filing cabinets). Open those, and you have folders that have month-day-year on their tab label. This makes it so you can quickly go through the folders sequentially quickly. If you did YYYYMMDD, you would need to ignore the first 4 numbers. DDMMYYY, the labels won't be in numerical order.
  Putting files back, you look for the correct year, but then it's easy to drop the folder back into it's numerical position.
  In a digital structure, filing records is automated and we can use a search function, so we do store digital files as YYYYMMDD.

Generally we say June 1, not 1 June or 1st of June... So 6/1 makes complete sense.
For anything "official", like a work spreadsheet, I'll use ISO format YYYY-MM-DD for clarity and ease of filtering/sorting.
- Who is "we"? Americans? I usually hear Americans say "June 1st," not "June 1."
  
  Are you really going to nitpick over the st and ignore their entire point?
  
  We meaning USAians, since we're the kinda the only ones who use Month-Day
  It's just an example. We say June first, that's why we write 6/1

It's not just Americans. There are many countries in Asia where the default is year month day. If you ever had to organize files by name and date this is the supreme sorting order. Both Europe and North America are getting it wrong.
If this gets you mad don't ever look into how the French count from 80 to 99. Or how languages disagree on what's blue or green. These things happen.
- I know about the Asians. I work in a Chinese run company and we use WeChat for internal communications. When I have to search for a message from a specific date I always get confused by the way the dates are displayed.

Hello, have you heard the good word of our lord, ISO-8601?
- That's the correct way.
- It solves the problem ;P
- Yes I did! And it seems like my savior!

It comes down to the variable weather in the US versus the UK.
The UK has maybe handful of weeks of actual hot weather, months and months of rain, and then some weeks of bitter cold. The day is more important than the month who cares if it’s March or September? It’s another day of rain and grey.
The US has extreme weather changes across the year, especially in the northeast where differences in US and UK English first began to diverge, intentionally and unintentionally. In a state like Massachusetts, knowing the month is important for things like setting the scene in letters “home” and so forth. The summer months and grossly hot. The fall/autumn is full of brilliant colors and mild weather followed by months of bitter, unrelenting cold winter. The spring months yield to green and mild weather again. Knowing that the month is April is very important because the 4th of April is going to be incredibly different from the 4th of September.
Source: Link
- You little shit
- LOL OK, thanks for the laugh regardless.

I don't have a clue why we do MM-DD-YYYY and personally I hate how dates are done in the west, to a degree.
For a maths course I've been taking at college, I never use MM-DD in my notebook because that and DD-MM are stupid in my opinion. I always spell out the month first to ensure I don't get mixed up. I honestly envy that some languages like Chinese and Japanese have an individual character to help distinguish between month and day.
Also, I would love if every country using the MM-DD or vice versa format could all agree on which format to use for everyday things.

Idk, maybe like all U.Sians traditions, this was an Old-World British thing Americans preserved, since it's a more direct term of the English language, more direct than Day then Month
so unless it's a special day, if not holiday, for U.Sians like 4th of July, by default, Month then Day

My guess is the month is most relevant to an agrarian society. It tells you where you are in the growing cycle that the entire culture revolves around. The day and year offer little practical utility to a 19th century farmer.
- Oh, that make more sense and seems plausible! Thanks!

Because Star Wars day sounds better when you say “May the Fourth be with you”. That said, I could be convinced to switch to Yoda-style “With you, the Fourth May be”.

I don't know, that's just how I learned it in school so it feels natural for me to use/say.
This post kinda stinks of "why doesn't the US just switch to metric? Are they stupid?"
- Sorry if it gives that impression, it is not at all my intention, it is pure and honest curiosity. That's why I avoided any bad word and put it in a subjective point of view ("I think / I believe")
- Not switching to metric is stupid. Fighting for independence from the empire, but then clinging to the imperial system that has only disadvantages over the metric system - that just screams not driven by reason

regardless of the month, I think what matters first is to know what day of the month you are in
You're telling me that if you have a list of scheduled dates in the near future to meet with clients/patients/whatever, you first want them sorted by day, and then month?
So this list is the order you want to see these in?
4/5/25
8/7/25
15/6/25
16/5/25
23/6/25
Doesn't it make way more sense to see them sorted by month first, then day, so that they're actually in chronological order.
5/4/25
5/16/25
6/15/25
6/23/25
7/8/25
The only way you could defend the former listing is if you're also arguing that it makes sense to sort the list by the middle column, and hopefully we all agree that is just absurd. We don't alphabetize people by their middle names. You don't look up a word in the dictionary starting with the letter in the middle.
I jest, but I think this illustrates a real-life, commonplace example of when it makes sense. I agree that MM/DD/YYYY is not in order of magnitude, but I do believe it's in order of most significance to least significance given the timescales we are typically dealing with.
- Such a waste. 2025-06-01. Easy. Chronological.
  
  So,
  OP is asking why month before day rather than day before month
  In your example, it's not clear whether you are doing Y-M-D or Y-D-M, but I assume you are putting month before day, so we agree on that part. But
  I think we're all in favor of: Most significant on the left -> Least significant on the right. I'm just arguing that, most if the time, for the most common uses, Month is most significant. It's just more common that you're looking at a list of dates that all span the next few months than a list of dates that are all within this month, or beyond a year.

Out of curiosity: do you also find it weird that (I'm assuming) you use hour:minute order when reading the clock, instead of minute:hour? Would saying the minute first make more sense to you?
- This is already done often.
  Quarter after 4 aka 4:15
  10 to 5 aka 4:50.
  Half past noon aka 12:30
- No

Idk but I think it works best for us. I like how July 4th 2025 sounds over 04 July 2025. Call it cultural differences I suppose and that's that.

You already answered your own question, bud.
it doesn't make sense TO ME. Based on what I was taught
Why do you think other people are different than you?
- I'm just curious... Is that a crime?

Why, when you want to know the time, do you read the hours first then the minutes? Why not just read the minutes and then figure out the hour you're in?
- Convenience...? Is it more convenient to know the month first and the day second? (That's literally what I'm just asking! No shade! No judge! Only curiosity!)