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Tell HN: Sudden Chile daylight savings time rules change causes chaos

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Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#81

Post by AndreasHae »

toast0 wrote: post #26
MobiusHorizons wrote: post #22

Earlier quoted context omitted.

It’s one heuristic, but you can’t know what they want, the problem is underspecified. It’s reasonably likely they could want a reminder to watch a game that is being broadcast from a different time zone, or call a friend in a different country.

The user interface can be akward, but you can ask them for the timezone of the event. If it's for a live event in another place, they would ideally put in the local time in the other place and the timezone there. Or if it's a fixed time, not to be moved by DST changes anywhere, they could specify it in UTC. It's also a good idea to calculate and save the offset when editing. Then, if the offset changes later, you can…

A lot of this could be solved by inferring the time zone by location of the appointment. If you know the event occurs in a specific place at a specific time, you almost certainly want it to be the standard time zone of that place. If that place uses DST, I couldn’t think of any reason to ignore it and opt for standard time regardless.

Bonus: geopolitics change country lines, and that affects time zones as well. When the time zone at the appointment location changes due to border conflicts, you can get the new time zone without having to change anything.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#82

Post by delecti »

kragen wrote: post #75
delecti wrote: post #73

Earlier quoted context omitted.

I've mostly given up being pedantic about the difference between PT, PDT, and PST. Most people mean "PT" when talking about the time that work meetings are scheduled, but they say "PST" basically year-round, despite it being PDT more often than PST.

It's not a pedantic difference; if you calculate the time as PST when it's PDT or vice versa you'll be an hour off. Holding a meeting an hour early or attending it an hour late can have serious consequences.

I agree that it's an important difference, but being insistent about it is excessive because functionally those kind of mistakes just don't happen when scheduling meetings in Outlook, which is the context where it matters.

Most of my work meetings only involve people in the same city, so there's no confusion there, and thus no scheduling problems. And 99% of the rest of my meetings are with people in Europe, and the relative difference between PST and CET is the same as the relative difference between PDT and CEST (though I do have to remind people twice a year that the two time zones change to/from DST a week or two apart).

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#83

Post by jkaplowitz »

toast0 wrote: post #26
MobiusHorizons wrote: post #22

Earlier quoted context omitted.

It’s one heuristic, but you can’t know what they want, the problem is underspecified. It’s reasonably likely they could want a reminder to watch a game that is being broadcast from a different time zone, or call a friend in a different country.

The user interface can be akward, but you can ask them for the timezone of the event. If it's for a live event in another place, they would ideally put in the local time in the other place and the timezone there. Or if it's a fixed time, not to be moved by DST changes anywhere, they could specify it in UTC. It's also a good idea to calculate and save the offset when editing. Then, if the offset changes later, you can…

There should also be a way to say "my current local time, whatever that may be", such as for events reflecting a personal daily routine for exercise, medicines, etc. This should adjust accordingly as the person changes time zone instead of staying at a fixed UTC offset.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#84

Post by Volundr »

kragen wrote: post #75
delecti wrote: post #73

Earlier quoted context omitted.

I've mostly given up being pedantic about the difference between PT, PDT, and PST. Most people mean "PT" when talking about the time that work meetings are scheduled, but they say "PST" basically year-round, despite it being PDT more often than PST.

It's not a pedantic difference; if you calculate the time as PST when it's PDT or vice versa you'll be an hour off. Holding a meeting an hour early or attending it an hour late can have serious consequences.

It is a pedantic difference. While it's technically incorrect to say PST when it's currently PDT, it doesn't inhibit communication. Both parties will understand it to be that "we meeting at 9am, whenever that happens to be for our California staff" as opposed to "we are meeting at 9am PST, even though no one is currently on PST"

Even my colleague in Arizona is able to follow this despite them not joining the daylight savings time.

Technically incorrect but in a way that doesn't inhibit understanding is the definition of pedantic.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#85

Post by toast0 »

AndreasHae wrote: post #81
toast0 wrote: post #26

Earlier quoted context omitted.

The user interface can be akward, but you can ask them for the timezone of the event. If it's for a live event in another place, they would ideally put in the local time in the other place and the timezone there. Or if it's a fixed time, not to be moved by DST changes anywhere, they could specify it in UTC. It's also a good idea to calculate and save the offset when editing. Then, if the offset changes later, you can…

A lot of this could be solved by inferring the time zone by location of the appointment. If you know the event occurs in a specific place at a specific time, you almost certainly want it to be the standard time zone of that place. If that place uses DST, I couldn’t think of any reason to ignore it and opt for standard time regardless. Bonus: geopolitics change country lines, and that affects time zones as well. When…

That works if you know the location of the appointment. But if you're going to a bar to watch a televised game with friends, the location in the appointment is probably the bar, but the timezone is wherever the game is held. If you're going to have a conference call and you have a shared calendar system, great everybody should agree; if all the participants have separate calendar systems, maybe you discuss the time to have the call and each enter it in your local time, which works fine until someone's government adjusts local time on short notice. Having separate appointments sounds fragile, but have you had a good experience with cross domain calendaring? I certainly haven't.

Never mind, if you had a fully booked schedule collaborating across timezones and someone's government adjusts local time, now you've got a mess.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#86

Post by smsm42 »

Israel used to have the switch data determined by a parliamentary vote, and changed almost every year. Depending on the political power distribution, the date was moved back and forth. I don't remember the exact details already, but it was related to Jewish holidays, which involved morning prayers, so sometimes it was more convenient for certain people to move the time scale back or forward, and since Jewish holidays are celebrated following Jewish calendar, which moves around relatively to Western calendar, and since sometimes religious parties had enough power to get special consideration and sometimes they didn't...

You can look at the result e.g. here: https://git.launchpad.net/pytz/tree/tz/asia (look for "Zion" there). They thankfully finally stopped doing it in 2013 and arrived at a stable rule, but until then you can image how much confusion it caused.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#87

Post by macintux »

delecti wrote: post #73
macintux wrote: post #36

Earlier quoted context omitted.

I can’t even get employees at the company where I work to understand and communicate EDT instead of EST. I don’t think calendaring tools are going to have much success asking people what timezone they want.

I've mostly given up being pedantic about the difference between PT, PDT, and PST. Most people mean "PT" when talking about the time that work meetings are scheduled, but they say "PST" basically year-round, despite it being PDT more often than PST.

Yet if we're encouraging people to select a timezone manually (context for this particular thread) it matters, because software is (usually) happy to do exactly what you tell it to do.

Mainly, though, it just annoys me: precision sans accuracy is bloody annoying.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#88

Post by toast0 »

jkaplowitz wrote: post #83
toast0 wrote: post #26

Earlier quoted context omitted.

The user interface can be akward, but you can ask them for the timezone of the event. If it's for a live event in another place, they would ideally put in the local time in the other place and the timezone there. Or if it's a fixed time, not to be moved by DST changes anywhere, they could specify it in UTC. It's also a good idea to calculate and save the offset when editing. Then, if the offset changes later, you can…

There should also be a way to say "my current local time, whatever that may be", such as for events reflecting a personal daily routine for exercise, medicines, etc. This should adjust accordingly as the person changes time zone instead of staying at a fixed UTC offset.

that's "floating time" and is definitely a valid option too, although for uses with multiple devices, now they've all got to agree on which timezone the user is currently subject to if you want a consistent experience.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#89

Post by elashri »

petre wrote: post #64
wging wrote: post #61

Earlier quoted context omitted.

Morocco did the same thing in 2018 - less than two days' notice. https://www.bbc.com/news/world-africa-45995634

Quoted post unavailable.

Why would they change for Ramadan? the fasting times are determined by sun rise and set. It is not going to change and prayer times wouldn't be affected ( except the numerical shift of time only).

The second part about arab world are not correct through. I grew up in Egypt which used to have daylight saving change but this ceased to happen from 2011 I think.

Re: Tell HN: Sudden Chile daylight savings time rules change causes chaos

#90

Post by mike_hock »

hilbert42 wrote: post #70
mike_hock wrote: post #55

Earlier quoted context omitted.

No, the fundamental problem is that DST is an ill-conceived concept, and being forced to inscribe it in software exposes all the contradictions and inconsistencies. As another poster said, when is 1:30am on November 6th in Ontario? The only thing this has to with computers is that we do all organizational stuff with computers nowadays. Changing DST on short notice would have caused chaos in the 19th century as well.

"an ill-conceived concept," That's just an opinion, not an absolute fact. There's nothing fundamental about it. After all, over the last hundred years or more most countries have had DST so that's the opposite opinion - and for DST to be so widely adopted many millions thought it was a good idea. I'm only stating facts. Frankly, I couldn't give damn whether we had DST or not and I can never understand why people get…

I literally lose sleep twice a year over DST :D

Yes, twice. When the clock suddenly moves back, that also causes jetlag.

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