For me, the most annoying part of the MM/DD/YY is that the unit of time lengths are out of order. In what other context would you put the middle length first, then the shortest, then longest. Would be like saying I ran my marathon in 44 minutes, 14 seconds, and 3 hours
Even in the states, the US Military writes dates (in my experience) almost exclusively as 20SEP2026, with the occasional 20260906 on some paperwork or 20 September 2026 on memos. An extremely American organization that perhaps values unambiguous communication to a fault (looking at you 24hr time) agrees with you
Nice yeah, great example. As an aside I always chuckle when Americans call 24-hour time “military time”, as if the military was even close to being the main user of this! Though I don’t really mind the 12-hour default in English
MM/DD/YY is the best way because, the month is the primary unit of measure relative to the year you are referring to. I remember going on Spring Break in March 1993. Our oldest childest was born in September of 2000.
You would never refer to an event on the day of the year. You woudn't say you were born on 109th day of 1972 or that Christmas falls on the 359th day of 2026.
The primary unit of measure is the the month, subdivided into managable pieces.
Of course! I mostly agree with you, really, months are the most intuitive unit of the three and often the most useful. And that's why, IMO, it should usually be spelled out; this is more useful than putting it first but in number form.
MM/DD/YY is customary and sentimental, readily understood by the vast majority of people I interact with, and using a different format would be more confusing to them. These aren't just reasons to use it, contra your title, they're very good reasons. Of course, we're all entitled to our sentimental attachments and frustrations, you no less than me.
When there's a good reason to use a different abbreviation, though, I do.
Well yes, I did say that conventions are powerful! They are in some sense often strong and sufficient reasons to not change things — e.g. at this point it's going to be QWERTY forever on keyboards — but in another sense when convention is all you have it's kind of a weak position to be in, rationally. And conventions can change!
Hmm. Personally, I don't like switching between words and numbers. And there are many contexts in which the year is sufficiently contextual. For instance, dating the pages in the planner that I'm using this year. So the question for me is there MMDD vs DDMM. And functionally, putting the month at the front makes it easier to flip through and find what I'm looking for. There are many rational arguments against MMDDYY and really only one good one: it's very practical.
I'm with you on Fahrenheit -- except when it comes to the weather. How hot is is outside? 100 heat units. Wow! I assume that's hot? And in the winter, how cold does it get. Around 32 heat units. Sounds cold! But when things are very very cold, they may even get down to 0! But when I brew my coffee, my kettle is set to Celsius, no contest.
In general I am in favor of rationalizing time. It's a travesty that September is the 9th month, it makes no sense whatsoever that this is the year 2026, and we could reconfigure months and weeks and time zones to be much much more sensible. But these two examples are instances where I think practicality overrules rationality.
And for what it's worth, I'd wager I'm in the 95th percentile of Americans in terms of my willingness to reconsider such things, so the argument is all a bit of candy floss.
American here but yeah, I mostly agree. I actually tend to default to YYYY-MM-DD even in non-technical contexts because it's the least ambiguous. Most people can figure it out eventually, and absolutely no one is going to mistake it for YYYY-DD-MM because nobody uses that form.
That said, you leave Fahrenheit ALONE. I realize I'm probably just giving you more ammunition here but IMO the single best characteristic of the Fahrenheit scale is the fact that "one degree" is just about the threshold of human perception. In other words, 72 Fahrenheit is *just barely* noticeably different from 71 Fahrenheit, which is exactly what you want for a temperature scale whose primary use case is representing temperatures as perceived by humans (weather, thermostat settings). (Obviously if you're doing scientific work then sure, go ahead and use Celsius, or even better use Kelvin, because either one of those is more objective from a scientific standpoint.)
Haha, longer piece coming, but my AC is Fahrenheit-only for some reason and you can only change the temperature by increments of two degrees (72, 74, 76, etc.) which suggests to me that a one-degree difference would not perceivable enough to make it into this commercial product
(Ok to be fair it’s an old model by a Japanese brand and “made in the P.R.C.” so not the most American thing, but since it’s Fahrenheit-only I assume it was made for the US market and they assumed it would be more practical to Americans to use increments of two, though maybe it works in Celsius internally. I shall investigate)
That's actually really weird, I've never seen a thermostat that functions like that and all the thermostats I've lived with have used Fahrenheit because, of course, I live in the US.
Internally using Celsius and converting to Fahrenheit for display seems possible, and in fact was the first thing that occurred to me before I read your second paragraph. Although on second thought - probably not, because then you'd get the occasional situation where pressing the button once changes the temperature by 1 or 3 degrees, since Fahrenheit : Celsius is not exactly 2 : 1.
Anyway, "adjust the thermostat by one degree Fahrenheit" is not an uncommon action for me and mine, so there's one contrary anecdote, at least.
Fahrenheit is nicely calibrated to human perception in that 0 is really damn cold and 100 is really damn hot and almost all weather we experience in the year fluctuates nicely in this range
I think ultimately it is futile because part of why America has these weird conventions is to show that it has the power to ignore everyone else's (see the metric system) but on my computer I have dates appear like “21 Sep 2026”
I once had to clean up a research group server that had millions of files on it created between 2001 and 2012. That meant all the MM references used could also be YY years. made more of a nightmare because all the Americans using the server ignored the Australian institutional standards and used MM/DD/YY instead - intermingled with DD/MM/YYYY files and folders.
For me, the most annoying part of the MM/DD/YY is that the unit of time lengths are out of order. In what other context would you put the middle length first, then the shortest, then longest. Would be like saying I ran my marathon in 44 minutes, 14 seconds, and 3 hours
Always ISO 8601 FTW! 🤓
It always struck me as a weird way of working.
Day month year is a pattern of the smallest to the largest social is much cleaner.
We can say
20 September as easily as September 20.
But nothing will change this.
Even in the states, the US Military writes dates (in my experience) almost exclusively as 20SEP2026, with the occasional 20260906 on some paperwork or 20 September 2026 on memos. An extremely American organization that perhaps values unambiguous communication to a fault (looking at you 24hr time) agrees with you
Nice yeah, great example. As an aside I always chuckle when Americans call 24-hour time “military time”, as if the military was even close to being the main user of this! Though I don’t really mind the 12-hour default in English
YYYY-MM-DD is unambiguous and alphabetizes into chronological order
Yes that’s why I recommend it when one can’t use month names
J’ai eu une réflexion similaire en lien avec la documentation des dossiers médicaux. J’écris le mois en lettre le plus possible, sinon AAAA/MM/JJ.
Montréal, ville bilingue et même plus!
MM/DD/YY is the best way because, the month is the primary unit of measure relative to the year you are referring to. I remember going on Spring Break in March 1993. Our oldest childest was born in September of 2000.
You would never refer to an event on the day of the year. You woudn't say you were born on 109th day of 1972 or that Christmas falls on the 359th day of 2026.
The primary unit of measure is the the month, subdivided into managable pieces.
I notice that you did not say "Spring Break in the 3rd month of 1993" or "born in the 9th month of 2000". Curious!
I hope you'll permit me my contrarianism to your well written and interesting piece!
Of course! I mostly agree with you, really, months are the most intuitive unit of the three and often the most useful. And that's why, IMO, it should usually be spelled out; this is more useful than putting it first but in number form.
Ah, the good ol’ date and date time formats. Keeping programmers awake at night since at least the 1960’s
MM/DD/YY is customary and sentimental, readily understood by the vast majority of people I interact with, and using a different format would be more confusing to them. These aren't just reasons to use it, contra your title, they're very good reasons. Of course, we're all entitled to our sentimental attachments and frustrations, you no less than me.
When there's a good reason to use a different abbreviation, though, I do.
Well yes, I did say that conventions are powerful! They are in some sense often strong and sufficient reasons to not change things — e.g. at this point it's going to be QWERTY forever on keyboards — but in another sense when convention is all you have it's kind of a weak position to be in, rationally. And conventions can change!
Agreed! I merely object to the post's title.
Hmm. Personally, I don't like switching between words and numbers. And there are many contexts in which the year is sufficiently contextual. For instance, dating the pages in the planner that I'm using this year. So the question for me is there MMDD vs DDMM. And functionally, putting the month at the front makes it easier to flip through and find what I'm looking for. There are many rational arguments against MMDDYY and really only one good one: it's very practical.
I'm with you on Fahrenheit -- except when it comes to the weather. How hot is is outside? 100 heat units. Wow! I assume that's hot? And in the winter, how cold does it get. Around 32 heat units. Sounds cold! But when things are very very cold, they may even get down to 0! But when I brew my coffee, my kettle is set to Celsius, no contest.
In general I am in favor of rationalizing time. It's a travesty that September is the 9th month, it makes no sense whatsoever that this is the year 2026, and we could reconfigure months and weeks and time zones to be much much more sensible. But these two examples are instances where I think practicality overrules rationality.
And for what it's worth, I'd wager I'm in the 95th percentile of Americans in terms of my willingness to reconsider such things, so the argument is all a bit of candy floss.
To be fair, the Asian YY/MM/DD is the most logical to me. From biggest to smallest just makes the most sense!
American here but yeah, I mostly agree. I actually tend to default to YYYY-MM-DD even in non-technical contexts because it's the least ambiguous. Most people can figure it out eventually, and absolutely no one is going to mistake it for YYYY-DD-MM because nobody uses that form.
That said, you leave Fahrenheit ALONE. I realize I'm probably just giving you more ammunition here but IMO the single best characteristic of the Fahrenheit scale is the fact that "one degree" is just about the threshold of human perception. In other words, 72 Fahrenheit is *just barely* noticeably different from 71 Fahrenheit, which is exactly what you want for a temperature scale whose primary use case is representing temperatures as perceived by humans (weather, thermostat settings). (Obviously if you're doing scientific work then sure, go ahead and use Celsius, or even better use Kelvin, because either one of those is more objective from a scientific standpoint.)
Haha, longer piece coming, but my AC is Fahrenheit-only for some reason and you can only change the temperature by increments of two degrees (72, 74, 76, etc.) which suggests to me that a one-degree difference would not perceivable enough to make it into this commercial product
(Ok to be fair it’s an old model by a Japanese brand and “made in the P.R.C.” so not the most American thing, but since it’s Fahrenheit-only I assume it was made for the US market and they assumed it would be more practical to Americans to use increments of two, though maybe it works in Celsius internally. I shall investigate)
That's actually really weird, I've never seen a thermostat that functions like that and all the thermostats I've lived with have used Fahrenheit because, of course, I live in the US.
Internally using Celsius and converting to Fahrenheit for display seems possible, and in fact was the first thing that occurred to me before I read your second paragraph. Although on second thought - probably not, because then you'd get the occasional situation where pressing the button once changes the temperature by 1 or 3 degrees, since Fahrenheit : Celsius is not exactly 2 : 1.
Anyway, "adjust the thermostat by one degree Fahrenheit" is not an uncommon action for me and mine, so there's one contrary anecdote, at least.
Fahrenheit is nicely calibrated to human perception in that 0 is really damn cold and 100 is really damn hot and almost all weather we experience in the year fluctuates nicely in this range
Thanks for reiterating one of the silly arguments I was talking about! :)
Of course!
Hehe. But I do think it makes some sense that the weather outside varies between 0 and 100 rather than between -17 to 38 or so
I think ultimately it is futile because part of why America has these weird conventions is to show that it has the power to ignore everyone else's (see the metric system) but on my computer I have dates appear like “21 Sep 2026”
I'm American, but this makes sense to me.
I once had to clean up a research group server that had millions of files on it created between 2001 and 2012. That meant all the MM references used could also be YY years. made more of a nightmare because all the Americans using the server ignored the Australian institutional standards and used MM/DD/YY instead - intermingled with DD/MM/YYYY files and folders.
I hope you managed without any lasting trauma!