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Tell HN: My usability pet peeve – am/pm times with a leading zero

25 points by FearNotDaniel ↗ HN
I don't know why I've started noticing this a lot more recently on websites, but it seems to be getting more common to see times-of-day stated in the am/pm format but still using a leading zero on the hour. E.g. "03:00 pm" instead of "15:00" or "3:00 pm". My brain has got so used to parsing the 24-hour clock such that I see a leading zero and assume it's a morning time, then there is the moment of cognitive dissonance when I spot the "pm" and have to recalculate in my mind (especially if the time in question is in a foreign time zone). Does anyone else anecdotally get this? Has anyone measured whether it is a problem on a larger scale?

59 comments

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filleokus
A similar issue, but perhaps not as bad, is the incorrect use of currency identifiers, like "SEK 100" ("$10"), or incorrect decimal symbols.

Another interesting case I've seen sometimes is when people are helpful and convert from imperial to metric units, but don't change the underlying value. Stuff like comparisons, "price per 28.3 grams" ("price per oz").

Units and locales are hard.

StavrosK
What, you don't measure things in multiples of 28.3 grams?
hexo
We have standardized 13.37 gram units here
taneq
> Stuff like comparisons, "price per 28.3 grams" ("price per oz")

This stuff happens all the time. PCB components with 2.54mm pin spacing. Dressed pine only available in 900mm, 1800mm, and 2400mm lengths. Heck, even 600mL iced coffees...

tluyben2
My pet peeve is am/pm time; I have no clue why people use it vs 24 hour clocks. Even worse when people leave off the am/pm; 'the meeting is today at 2!'.
StavrosK
If that's what irks you, you've never had to schedule a meeting with someone who thinks their timezone is GMT when it's actually BST.
tluyben2
Yeah, another pet peeve is not using UTC for everything everywhere in business situations. I have i3wm running with my local time + UTC time in the bottom, so I mail people with 'the meeting is 14:00 UTC'.
StavrosK
Yes! Or people in another timezone telling you "the meeting is at noon today". Just goddamn tell me "it's in three hours from now", or at least give me UTC, why do you have to make me convert from your timezone? But no, if I tell people "the meeting is at 7pm EEST", I'm being difficult.
MisterTea
If this is work related surly there would be no ambiguity when reading 2 as 2pm or 1400.
tluyben2
There is; I work with teams / partners in the US/EU/AU. Ofcourse I can just check the person who writes it and jump to their time frame, but why not just say 14:00 and preferably a timezone.
reaperducer
The people I work with add city names after times when they're speaking to people in mixed geographies.

They say "today at noon, Chicago time." Or "9am Los Angeles."

It's become so habitual that they'll even use a city name without thinking if they need to. For example, saying "4pm Biloxi time" to someone in Chicago, which is the same time. But at least it eliminates any ambiguity.

tluyben2
It would there :) Anywhere outside the US, it would make no sense at all. I watched enough tv series to know this type of thing, but people who do not would have no clue what you are talking about... But yes, depending on your audience, do what works ofcourse.
Freak_NL
You expect the meeting to be held in the middle of the night? 'The meeting is today at 2!' is unambiguous in most cases (certainly with a 9-to-5 job).

In many locales where the 24 hour clock is used, people refer to the hours after noon as one, two, three o'clock etc. Then when you write it down somewhere two o'clock becomes 14:00.

OP's pet peeve is kind of weird though. Even with a 24 hour clock writing 9:00 for 'nine in the morning' without the leading zero is quite common, if not prevalent.

elbows
I use am/pm because that's how I was taught to tell time growing up, and in my corner of the world (northeast US) nearly everyone uses it. "2 pm" is immediately meaningful to me, but to parse "14:00" I have to subtract 12 in my head. Even when the am/pm is left off, it's usually clear from context.

I'm not arguing for the inherent superiority of am/pm notation, but I do get frustrated with people who use 24-hour time because "it's more logical", without seeming to realize that it's more difficult for the majority of people to understand.

tluyben2
> majority of people to understand.

Depends where / with who you work? Most of my colleagues have to think the same way about am / pm and often get it wrong when it's 12:00 am/pm.

The 'it's more logical' for me does apply there; in the 24:00 you cannot get 12:00 or 00:00 wrong no matter how you think about it. It feels intuitive in every way.

12 hour clocks made sense when clocks had 12 hours on them; then you had to somehow indicate which block of 12 hours; that problem was fixed before I (and probably you) were born though.

1_player
I grew up with 24-hour clocks, and I always get confused by the 12h version of midday and midnight.

Literally, the mnemonic I use to remember which is which is "it's the one that doesn't make sense".

So 11am then 12pm

And 11pm then 12am

(Whereas I would expect the 12th hour of the morning to follow the 11th of the morning, but it's actually the other way around)

dijit
This is exactly the same defence people have about the imperial system. (I'm british so have the 'benefit' of having both systems existing in my head as a weird mish-mash).

I can take it as a "con" against any new system, but it doesn't outweigh all other benefits- if it did then there'd be no progression in society -ever-

wattengard
You don't subtract it though. Once you are used to it your brain just correlates 14 with 2 and 17 with 5 and 23 with 11 without thinking. In Norway, and I think in most of the 24-hour world, we still use the 12hr clock in speech. I don't go around saying that "the clock is quarter past fifteen", I say "quarter past three" and the context usually makes it clear when I'm talking about.
gpvos
Indeed. It is written 15:15, but pronounced three-fifteen (or quarter past three etc.).
nextlevelwizard
do people actually say "fourteen oh-oh"?

I've used 24 hour clocks all my life and everyone uses 1-12 when talking. If someone is coming to see you at 14:00 they will say: "see you at two". We only use the proper format when writing.

sonofgod
I wouldn't say "fourteen oh-oh", but "fourteen hundred", and I've rarely heard just "fourteen".

Extends obviously to "fourteen thirty".

(Northern England)

gpvos
Interesting, I thought that -hundred or even -oh-oh was an American thing, originating in their military. (Non-native speaker from the continent.)
tluyben2
No, in speech/direct chat you would say 2 indeed, but not when it can be confusing. When there is any doubt, even on the phone when making an appointment I always repeat the time in 24 hour format if the appointment is more than 12 hours away. Just to make sure.
[dead] track_me_now
>> I have no clue why people use it vs 24 hour clocks. My Guess: You're under 35 years old. There was a time before digital clocks and, despite a recent job interviewee in their 20's who told me "it didn't say so I assumed it wasn't a 24-hr [analog] clock", it makes more sense when your time tracker can only do 12-hr increments - especially when coupled with a much smaller world that didn't need to prevent ambiguity on a global scale.

Ideal? no - but there are many things that make a little more sense when you start thinking about how they came to be vs. just the end state (like most software code you will encounter in your life).

So please, please work to change them, but don't outright dismiss them as wrong, dumb or the product of an inferior mind.

Oh - and I will not be attending your 2am meeting.

gshdg
Because we learned to tell time on 12-hour analog clocks?
majewsky
I always quip that if I were to achieve world domination, my first decree would be about harmonizing all these bullshit idiosyncrasies that we developers have to deal with. 24-hour format everywhere. Metric system everywhere. Celsius everywhere. And so on.
jazoom
Go straight for Kelvin
lioeters
How would you unify timezones? That's a ball of idosyncrasies if I've ever seen one..
majewsky
That's a really good question. I omitted timezones from my list because I don't have a proposal at hand there.

Same for "first day of the week": For me it's obviously Monday, but I think the Jews have a religiously-grounded opinion on it being Sunday. That's a hornet's nest I'd rather not stir up until I've actually achieved world dominion. :)

szatkus
Don't forget about short and long scale.
PunksATawnyFill
Even worse: Apple's "time-zone support" in their iOS calendar, which changes the times of your appointments behind your back.

If you buy plane tickets and then enter the dates and times in Calendar... Apple will change them without telling you if you travel through time zones. AS IF ANYONE ENTERS TIMES LIKE THAT.

If I have a meeting in London next week at 10 a.m. on Tuesday, I'm not going to sit here in the U.S. and do the math so I can enter the meeting time at some crazy hour to "fool" Calendar.

DEAR APPLE: WE WANT THE ALARM TO GO OFF WHEN THE CLOCK ON THE PHONE SAYS THE TIME FOR WHICH I SET THE ALARM.

This is NOT an option on iPhones currently. Unfuckingbelievable: https://goldmanosi.blogspot.com/2016/03/apples-idiotic-time-...

richrichardsson
Google Calendar is also guilty of this nonsense, I missed a flight exactly for this reason.
jazoom
I came very close to missing a flight because of this too. It's ridiculous.
devadvance
At least for Google Calendar, it's pretty easy to avoid the mental math by using the built-in time zones. You can select the time zone when creating the event[0].

[0] https://support.google.com/calendar/answer/37064

reaperducer
iOS does this, too. There's and entry for "time zone" immediately beneath the time setting spinny thing.
raxxorrax
heh, that would never have happened on my lineage smart brick, were the alarm app just goes to sleep as well. Certainly a most non-invasive app..

But yeah, this seems to be a bad design decision.

Let us meet in 4 hours in a different time zone doesn't seem to be a likely scenario. And even then it wouldn't make that much sense.

bo1024
The best approach seems to be making a date+time either "timezone aware" or "naive" (I got this from python's datetime.)

Naive dates don't have a timezone attached, so of course there's no auto conversion. Aware times do.

Now all you have to do is avoid assuming which your user wants. Especially avoid an interface that makes it look like they have a naive date when they actually have an aware one.

For example, if the appointment is timezone-aware, then write the timezone next to it! So if the user writes 10:00 and you auto-convert that and print 10:00 EST, they at least have a chance to correct it.

ed312
I never thought of this, but if it behaved as you suggest I would be raging the same! I work with teams across multiple timezones so I generally assume I need to adjust the time to convert to where it would appear on a local calendar. The only time I’ve been burned by this is the google “auto crest calendar entry” feature that put a show start time in the wrong time zone.
fouc
"Siri, remind me about appointment on tuesday next week at 10 am london time"
reaperducer
If I have a meeting in London next week at 10 a.m. on Tuesday, I'm not going to sit here in the U.S. and do the math so I can enter the meeting time at some crazy hour to "fool" Calendar.

I used to have this problem. I don't know if Apple fixed it or I just got used to doing it the Apple way. I think it helped to enter flights and appointments on the computer where there was more screen space to grok what was going on.

The key seems to be making sure to set the local time zone for both the departure and arrival locations. And if you need an alarm, to set it to "3 hours before" the appointment, rather than at some assumed local time.

I used to have the same problem you describe, but haven't had it in several years, even for flights and appointments across the International Date Line.

mcv
The obvious way to handle this would be to set the appointment for either the current timezone, or the timezone where the appointment takes place. Simple checkbox/radio button, pick a default, but let the user change that default.
falcolas
Respectfully, the current behavior is absolutely correct - associate a calendar entry with a time zone (and make it simple to adjust which time zone it is). Not doing this would make re-occurring meetings challenging to attend the moment you travel across a time zone, or when you invite people who are in a different time zone (such as international).

Personally, I do this kind of travel 4-5 times a year for work, and I am quite happy I don't have to add obscure time zone math on the top of an already disrupted mental state.

Time representations, especially for something as essential to modern life as a calendar, should be precise. Apple and Google's versions are precise.

ggambetta
Lately I've tended to use military time even in very informal circumstances, although only in written form. E.g. I'd text my GF "dinner w/friends Saturday 2000?".
Spooky23
The biggest temporal fail of the web is date. For some topics, it’s impossible to tell whether the author was working in 2012 or 2019.
theandrewbailey
Especially on blogs where the design only gives the month and day, and it's impossible to find out which year, because that's the only date to be seen on the page.
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alexvoda
This is potatoes. Want to rage? Read this: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/d77...

Who in their right mind thought YYYY-DD-MM is a good idea. (It's "smart", recognizes the YYYY part and moves it to the end and interprets as DD-MM-YYYY)

The ISO standard specifically used "-" as the delimiter for the standard date format because no one was using it. And MS had to ruin it.

troels
wtf

Brought to you by the same folks who figured that locale settings should determine how CSV is generated/interpreted.

taneq
> Who in their right mind

Probably the same people who thought MM/DD/YYYY was sensible?

StavrosK
At least that's far back enough that they aren't around for us to be angry at.
fouc
I don't see a problem with "03:00 pm" because I spot the : immediately. I see 2 digits and then 2 digits, so it's consistent.