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.

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.)

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.

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.

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.

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.

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.

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.

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.

ITT: defensive answers and ISO-8601 supporters.

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.

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.

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?

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.

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.

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.

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

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

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.

Hello, have you heard the good word of our lord, ISO-8601?

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.

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?"