[gvkhna]

Yes that works for most use cases but there are use cases where you may need to store or shuttle the time zone. For instance you want to know this UTC timestamp was originally created in PDT. You would have to store two variables. Most other languages have this functionality it can be useful and is good to have, probably only needed by Jedi’s too.

[netsharc]

The article gives an example, of you buying a coffee with your credit card while travelling to Sydney, and returning to Madrid, and a few months later seeing a charge for 3:50 AM on that date...

Google Photos also get confused with "When was this picture taken?", my older model camera just stores the EXIF date in "local time" and I have to remember to change its timezone when travelling, and if GPhotos can't figure it out, it might show pictures out of the airplane window, and then the next series of pictures are from the departure airport because they're from a "later" hour (since it's missing the timezone info).

I suppose I could keep it at my home time or UTC...

[chuckadams]

And if your spouse is checking the charges from Madrid, they probably want to see it in Madrid time. There is no single correct answer.

[lxgr]

Exif (fun exercise: find out who specifies it and when it was last updated!) actually didn't even have a way of storing timestamps in UTC or with zone information until fairly recently: It was all local times without zone information.

I've seen some software work around that by combining the local date/time with an embedded GPS tag, if present, which does contain the time in UTC.

[mminer237]

That is how I would expect a bank statement to read though. I would find it infinitely more confusing if I bought something online in my bank showed the time of wherever the seller was located.

The photos problem is harder, but the app needs to just convert it from local time to UTC when you import it. There's not much that can be done if you take photos on a camera with a different time zone than you're in without more metadata.

[nafey]

I have always wondered why breaking the timestamp (in UTC) and the timezone into two separate data points and storing both is not the accepted solution. It appears like the cleanest solution to me.

[Denvercoder9]

You can't accurately convert future local times to UTC timestamps yet, as that conversion changes when timezones change.

Let's say we schedule a meeting for next year at 15:00 local time in SF. You store that as an UTC timestamp of 2025-08-24 22:00 and America/Los_Angeles timezone. Now, imagine California decides to abolish daylight savings time and stay on UTC-8 next year. Our meeting time, agreed upon in local time, is now actually for 23:00 UTC.

[moqmar]

Two different implementations might make two different local times out of that, e.g. due to not being aware of changing DST/timezone policies. Hence the recommendation of separating between user/clock/calendar time (which must be exact to a human) and absolute/relative timestamps (which must be exact to a computer).

[tisdadd]

From my experience, it certainly is. Easy to tell time in sequence as well as local time then. When daylight savings hits you can still calculate well, and can quickly get real time for hours worked out drive time for freight across time zones to follow the hours of service rules.

[closewith]

You can make the same meme about this use case, too. One you get to the right, you realise you want two variables for this.