15 ms·

Another reason not to use EST/EDT is that they are overspecifying the time zone in most cases. If you ask for output in EDT, but the date is in December (which

Another reason not to use EST/EDT is that they are overspecifying the time zone in most cases. If you ask for output in EDT, but the date is in December (which is not part of daylight savings time) then should the date output be UTC-4 or UTC-5? Technically you asked for EDT. Using EST as a shortcut isn’t a good idea, either - most software will “know what you mean” and use EST or EDT appropriately... except, both The USA and Canada have been toying with the idea of dropping daylight savings time, so it’s very possible at some point in the future that 6:00pm on July 1st will be EDT in America/New York, but EST in America/Montreal (or vice versa). This is already true for CST - Saskatchewan doesn’t use DST. And there have been times where one country or another changes the start date or end date of DST too, so there’s no reason to assume those will always be the same between Canada and the US.

kenniskrag 6y ago
> toying with the idea of dropping daylight Europeans turn back clocks for daylight saving, perhaps for last time. source: https://www.dw.com/en/europeans-turn-back-clocks-for-daylight-saving-perhaps-for-last-time/a-55389492 https://www.dw.com/en/europeans-turn-back-clocks-for-dayligh...
- Hamuko 6y ago
  The EU DST debacle has been such a shitshow that I have trouble believing the words "perhaps for last time". And now with COVID-19, I haven't seen anyone actually focus on implementing the damn thing.
  - kenniskrag 6y ago
    What do you have to implement?
    - datejfktn 6y ago
      For once pretty much no one is aware of this supposed change. There was like a couple of articles on the day it was voted and that's it. This will 100% not happen, it's another one of those things that the EU parliament votes that everyone ignores, and it's perfect ammunition for those complaining that it makes laws without popular consultation. Trying to go forward with this change will generate massive anti EU backlash. And then you have the UK problem. Having variable time offsets between EU and UK would add yet another layer of disruption on top of Brexit.
      - iso1631 6y ago
        > For once pretty much no one is aware of this supposed change The consultation had 4.6 million responses. > Having variable time offsets between EU and UK would add yet another layer of disruption on top of Brexit. So?
        iggldiggl 6y ago
        > The consultation had 4.6 million responses. A disproportionate amount of which were from Germany (2/3 of the responses, even though Germany only is only ~ 16 % of the EU-population pre-Brexit).
      - Hamuko 6y ago
        >it makes laws without popular consultation That's not accurate. >This online consultation, which ran from 4 July to 16 August 2018, received 4.6 million responses from all 28 Member States, the highest number of responses ever received in any Commission public consultation. According to the preliminary results (see annex), 84% of respondents are in favour of putting an end to the bi-annual clock change.
        datejfktn 6y ago
        Selection effect. Those who really cared about this commented. But what about the 99% rest of population? It's a mistake thinking that because they dont realllly care they will accept either way. Resistance to change is huge, especially when it plays into the narrative "Bruxelles demanded it" And what I meant by lack of popular consultation is that if you go on EU streets and ask about this change 95% of people will have no idea what you are talking about.
        majewsky 6y ago
        No representative democracy is asking the electorate to vote on each and every bill. It defeats the purpose of having a parliament in the first place.
    - corty 6y ago
      The EU is currently one timezone for most of its area, the whole continent excluding Portugal (edit: and Finland, Greece, Baltic states) has the same timezone. But actually it should be 3 or 4 timezones if you want to be close to solar time. Also, there are people who would prefer having solar zone time +1 (so e.g. UTC+2 in Germany instead of UTC+1). The EU decided to chicken out and let the members decide for themselves. So now each country has to decide which timezone it would like to implement, and of course if a neighbour does it differently, you also got yourself a timezone boundary at your border, which people dislike. So now all the politicians are caught in a state of indecision, keeping the status quo.
      - Hamuko 6y ago
        >The EU is currently one timezone for most of its area, the whole continent excluding Portugal has the same timezone. That's definitely not accurate.
        corty 6y ago
        Oh, you are right, sorry. The Baltic states, Finland and Greece are UTC+2/3
        throw0101a 6y ago
        A good portion of the EU is in CET when they probably shouldn't be when it comes to solar time: * https://en.wikipedia.org/wiki/Time_in_Europe https://en.wikipedia.org/wiki/Time_in_Europe France should probably, AFAICT, be in WET (like the UK) and Spain definitely should be. Solar time offsets are quite off for them: * http://blog.poormansmath.net/how-much-is-time-wrong-around-the-world/ http://blog.poormansmath.net/how-much-is-time-wrong-around-t... * https://github.com/stefano-maggiolo/solar-time-vs-standard-time https://github.com/stefano-maggiolo/solar-time-vs-standard-t... * https://24timezones.com/world-time-zones#toc-0 https://24timezones.com/world-time-zones#toc-0
        kevincox 6y ago
        I hope that we can stop trying to sync noon to the local sun at some point. I think it made sense when communicating over distances was hard and rare. In that case giving local time some meaning (ex: "People tend to wake up around 8") had some value. However now that communicating with people around the word is commonplace I think that benefit is outweighed by the value of knowing what time people are talking about. Because if you try to schedule something before I want to wake up it is incredibly obvious to me. However if we mess up the timezone math by and hour no one will notice unless they think to explicitly check. The only real downside I see is that if the day number changes during your "day" it could be confusing. However I think we will quickly learn to deal with it (overnight shifts have been a thing forever and doctors seem to manage). Plus we already have a weaker form of this when we are talking about late-night activities so I think we will figure it out.
    - marcosdumay 6y ago
      Brazil spent 3 years talking to everybody, publishing the change, and making sure everybody was on the same page. Yet, all the companies providing software got it wrong at least once (some more than 3 times). The only software that got it right were community based FOSS distributions (not raspbmc... that got me). At least all the institutions got it right, so it was enough to announce "Windows|Red Hat|iOS|Android|whatever is wrong today, ignore it and use some other clock".
- leokennis 6y ago
  It will not happen. The science is overwhelming that having one timezone all year long is worse for people, and switching the clock back and forth twice a years is a minor nuisance at most. The EU's "Ban DST" is the same populist bullshit as Trumps "inject Windex to cure COVID". Based on nothing and ignorant at best. And the cherry on top is, if you ask the EU if they want to receive a no strings attached gift of €10.000.000.000.000 or €11.000.000.000.000, it would still take them 20 years to decide. No way they will ever reach consensus on DST.
  - etripe 6y ago
    If the science is overwhelming, do you have a source? If not, what are the downsides to having the same timezone all year?
    - kenniskrag 6y ago
      Never heard about windex. Now I know.
    - throw0101a 6y ago
      [Some links that I've posted the last few times DST has come up:] The folks who study this: * https://en.wikipedia.org/wiki/Chronobiology https://en.wikipedia.org/wiki/Chronobiology Seem to have come to a consensus that if we're going to get rid of DST, then health-wise it is best to have Standard Time year-round: > As an international organization of scientists dedicated to studying circadian and other biological rhythms, the Society for Research on Biological Rhythms (SRBR) engaged experts in the field to write a Position Paper on the consequences of choosing to live on DST or Standard Time (ST). The authors take the position that, based on comparisons of large populations living in DST or ST or on western versus eastern edges of time zones, the advantages of permanent ST outweigh switching to DST annually or permanently. * https://journals.sagepub.com/doi/full/10.1177/0748730419854197 https://journals.sagepub.com/doi/full/10.1177/07487304198541... For a longer-read, referencing quite a bit of academic literature, but a conclusionary snippet: > In summary, the scientific literature strongly argues against the switching between DST and Standard Time and even more so against adopting DST permanently. The latter would exaggerate all the effects described above /beyond/ the simple extension of DST from approximately 8 months/year to 12 months/year (depending on country) since /body clocks/ are generally even later during winter than during the long photoperiods of summer (with DST) (Kantermann et al., 2007; Hadlow et al., 2014, 2018; Hashizaki et al., 2018). Perennial DST increases SJL prevalence even more, as described above. * https://www.frontiersin.org/articles/10.3389/fphys.2019.00944/full https://www.frontiersin.org/articles/10.3389/fphys.2019.0094... Other position papers that I've dug up over the years when curiosity got the better of me: > Society for Research on Biological Rhythms (SRBR) is dedicated to advancing rigorous, peer-reviewed science and evidence-based policies related to sleep and circadian biology. * https://srbr.org/advocacy/daylight-saving-time-presskit/ https://srbr.org/advocacy/daylight-saving-time-presskit/ * (refs, with pro and con): https://srbr.org/wp-content/uploads/2020/09/DST-References-SRBRPressKit.pdf https://srbr.org/wp-content/uploads/2020/09/DST-References-S... European Sleep Research Society: * https://esrs.eu/wp-content/uploads/2019/03/To_the_EU_Commission_on_DST.pdf https://esrs.eu/wp-content/uploads/2019/03/To_the_EU_Commiss... Canadian Society for Chronobiology: * https://www.theglobeandmail.com/opinion/article-turn-back-the-clock-on-daylight-savings-why-standard-time-all-year/ https://www.theglobeandmail.com/opinion/article-turn-back-th... * https://twitter.com/ChronobioCanada/status/1190632096596926464 https://twitter.com/ChronobioCanada/status/11906320965969264... American Academy of Sleep Medicine (with 36 footnotes if you want to dig further): * https://jcsm.aasm.org/doi/10.5664/jcsm.8780 https://jcsm.aasm.org/doi/10.5664/jcsm.8780 * https://doi.org/10.5664/jcsm.8780 https://doi.org/10.5664/jcsm.8780 The Centre for Chronobiology, based at the Psychiatric University Hospital (University of Basel): * http://www.chronobiology.ch/wp-content/uploads/2019/08/JBR-DST.pdf http://www.chronobiology.ch/wp-content/uploads/2019/08/JBR-D... * http://www.chronobiology.ch http://www.chronobiology.ch (Personally, I'm just going to trust the experts on this as I don't have the energy to go digging in things. A quick cursory Google/DDG search is enough for me.)
jmgao 6y ago
> both The USA and Canada have been toying with the idea of dropping daylight savings time Individual states are toying with the idea as well [1], which presents a problem if one of the tzdata locations decides to change its rules. You're screwed no matter what you choose to do. :-( 1: https://www.syracuse.com/state/2020/11/state-senator-introduces-bill-to-end-daylight-saving-time-in-new-york.html https://www.syracuse.com/state/2020/11/state-senator-introdu...
- siculars 6y ago
  They already do. See Arizona.
  - 1-more 6y ago
    …and then see Navajo reservation in there, and then see the Hopi reservation inside of that!
- Izkata 6y ago
  It gets worse: DST in Indiana has to be handled on a per-county basis for anything prior to 2006. https://en.m.wikipedia.org/wiki/Time_in_Indiana https://en.m.wikipedia.org/wiki/Time_in_Indiana
  - spiralx 6y ago
    It gets worse: from when I had to deal with this some years back IIRC in Saudi Arabia the start and end of DST is set by decree every year.
Lvl999Noob 6y ago
On the topic of DST... can you explain why some countries use DST? Anytime I look for the reasoning of it, it says that DST helps "make better use of daytime" but how? The earth isn't gonna say "Damn! These people changed their clocks. I better change by rotation and give them more sun time." Whether you have DST or not, you still have the same amount of time with sunlight in a day.
- macintux 6y ago
  Just once I’d like to have a time zone discussion on HN that doesn’t devolve into pages of arguing about daylight saving time. If you search HN you’ll find plenty on this topic.
  - db48x 6y ago
    You'll have a happier life if your dreams are attainable.
  - klyrs 6y ago
    I mean, you're not wrong... but what else is there to talk about? Fact of the matter is, your preferences depend on where you live, your lifestyle, and the amount of time you spend on date&time fuckery in code. It's a contentious issue.
- mabbo 6y ago
  Golf courses. Well, okay, this is my wonderful father's half serious answer that I love to retell. The basic idea is that it's easier to convince everyone that is actually 5:00pm and time to leave work than it is to convince just your boss that you want to start work an hour earlier and leave and hour earlier. This problem is then applied to politicians and other powerful people, who want to go golfing after work. If there's no DST, the sun will set "earlier" according to the clock, and you can't get in a full 18 holes. So therefore, we change all the clocks so that powerful rich people can go golfing. No other group of people sees any benefits to DST.
  - Lvl999Noob 6y ago
phlo 6y ago
> If you ask for output in EDT, but the date is in December (which is not part of daylight savings time) then should the date output be UTC-4 or UTC-5? EST is always UTC-4 and EDT is always UTC-5. Both of these exist throughout the year. The only change happening in Spring/Autumn is that some places change which time zone they currently observe. This also addresses the second problem that you outlined. As long as the query is properly specified (if you want information related to a location, use America/New York; if you want information related to a time zone, use the time zone), you can always get an unambiguous and correct answer.
- throw0101a 6y ago
  > EST is always UTC-4 and EDT is always UTC-5. Except you have those reversed. :)
- dmm 6y ago
  To be pedantic EST and EDT are offsets. America/New_York is the timezone which consists of multiple offsets that depends on the time of year and date mostly determined by the local civil authority. For example in 2005, the US extended daylight saving time by four weeks. This difference between 2004 and 2006 is a part of the timezone.
  - phlo 6y ago
    Cool, I hadn't realized that distinction in terminology. Thanks for pointing it out! :)
- emmelaich 6y ago
  < EST is always UTC-4 Unfortunately not. Australia also used EST until recently. Now they've introduced AEST, but I'm sure there's systems out there using EST.
- mikelward 6y ago
  When somebody writes EST in summer they mean UTC-4. Interpreting that as UTC-5 is almost always wrong.
kelnos 6y ago
I (living in California) usually use "PST8PDT", which does what I want, all year round (for some irrational reason I refuse to claim that I live in Los_Angeles[0]). I believe there's also "EST5EDT", "CST6CDT", and "MST7MDT" as well. But agree that this is just a grab bag of confusing garbage. [0] I suppose if CA does away with DST (or keeps it permanently), I will have to change...
- boulos 6y ago
  Huh, your LA note prompted me to say “That’s why I use US/Pacific”. But someone on the internet tells me I’ve been doing it wrong and US/Pacific has been deprecated for years / I’m not supposed to: https://stackoverflow.com/questions/4309030/difference-between-timezones-america-los-angeles-and-us-pacific-and-pst8pdt https://stackoverflow.com/questions/4309030/difference-betwe...
kenneth 6y ago
I just always write ET, PT, MT, CT.

kenniskrag 6y ago

> toying with the idea of dropping daylight Europeans turn back clocks for daylight saving, perhaps for last time. source: https://www.dw.com/en/europeans-turn-back-clocks-for-daylight-saving-perhaps-for-last-time/a-55389492 https://www.dw.com/en/europeans-turn-back-clocks-for-dayligh...

Hamuko 6y ago
The EU DST debacle has been such a shitshow that I have trouble believing the words "perhaps for last time". And now with COVID-19, I haven't seen anyone actually focus on implementing the damn thing.
- kenniskrag 6y ago
  What do you have to implement?
  - datejfktn 6y ago
    For once pretty much no one is aware of this supposed change. There was like a couple of articles on the day it was voted and that's it. This will 100% not happen, it's another one of those things that the EU parliament votes that everyone ignores, and it's perfect ammunition for those complaining that it makes laws without popular consultation. Trying to go forward with this change will generate massive anti EU backlash. And then you have the UK problem. Having variable time offsets between EU and UK would add yet another layer of disruption on top of Brexit.
    - iso1631 6y ago
      > For once pretty much no one is aware of this supposed change The consultation had 4.6 million responses. > Having variable time offsets between EU and UK would add yet another layer of disruption on top of Brexit. So?
      - iggldiggl 6y ago
        > The consultation had 4.6 million responses. A disproportionate amount of which were from Germany (2/3 of the responses, even though Germany only is only ~ 16 % of the EU-population pre-Brexit).
    - Hamuko 6y ago
      >it makes laws without popular consultation That's not accurate. >This online consultation, which ran from 4 July to 16 August 2018, received 4.6 million responses from all 28 Member States, the highest number of responses ever received in any Commission public consultation. According to the preliminary results (see annex), 84% of respondents are in favour of putting an end to the bi-annual clock change.
      - datejfktn 6y ago
        Selection effect. Those who really cared about this commented. But what about the 99% rest of population? It's a mistake thinking that because they dont realllly care they will accept either way. Resistance to change is huge, especially when it plays into the narrative "Bruxelles demanded it" And what I meant by lack of popular consultation is that if you go on EU streets and ask about this change 95% of people will have no idea what you are talking about.
        majewsky 6y ago
        No representative democracy is asking the electorate to vote on each and every bill. It defeats the purpose of having a parliament in the first place.
  - corty 6y ago
    The EU is currently one timezone for most of its area, the whole continent excluding Portugal (edit: and Finland, Greece, Baltic states) has the same timezone. But actually it should be 3 or 4 timezones if you want to be close to solar time. Also, there are people who would prefer having solar zone time +1 (so e.g. UTC+2 in Germany instead of UTC+1). The EU decided to chicken out and let the members decide for themselves. So now each country has to decide which timezone it would like to implement, and of course if a neighbour does it differently, you also got yourself a timezone boundary at your border, which people dislike. So now all the politicians are caught in a state of indecision, keeping the status quo.
    - Hamuko 6y ago
      >The EU is currently one timezone for most of its area, the whole continent excluding Portugal has the same timezone. That's definitely not accurate.
      - corty 6y ago
        Oh, you are right, sorry. The Baltic states, Finland and Greece are UTC+2/3
      - throw0101a 6y ago
        A good portion of the EU is in CET when they probably shouldn't be when it comes to solar time: * https://en.wikipedia.org/wiki/Time_in_Europe https://en.wikipedia.org/wiki/Time_in_Europe France should probably, AFAICT, be in WET (like the UK) and Spain definitely should be. Solar time offsets are quite off for them: * http://blog.poormansmath.net/how-much-is-time-wrong-around-the-world/ http://blog.poormansmath.net/how-much-is-time-wrong-around-t... * https://github.com/stefano-maggiolo/solar-time-vs-standard-time https://github.com/stefano-maggiolo/solar-time-vs-standard-t... * https://24timezones.com/world-time-zones#toc-0 https://24timezones.com/world-time-zones#toc-0
        kevincox 6y ago
        I hope that we can stop trying to sync noon to the local sun at some point. I think it made sense when communicating over distances was hard and rare. In that case giving local time some meaning (ex: "People tend to wake up around 8") had some value. However now that communicating with people around the word is commonplace I think that benefit is outweighed by the value of knowing what time people are talking about. Because if you try to schedule something before I want to wake up it is incredibly obvious to me. However if we mess up the timezone math by and hour no one will notice unless they think to explicitly check. The only real downside I see is that if the day number changes during your "day" it could be confusing. However I think we will quickly learn to deal with it (overnight shifts have been a thing forever and doctors seem to manage). Plus we already have a weaker form of this when we are talking about late-night activities so I think we will figure it out.
  - marcosdumay 6y ago
    Brazil spent 3 years talking to everybody, publishing the change, and making sure everybody was on the same page. Yet, all the companies providing software got it wrong at least once (some more than 3 times). The only software that got it right were community based FOSS distributions (not raspbmc... that got me). At least all the institutions got it right, so it was enough to announce "Windows|Red Hat|iOS|Android|whatever is wrong today, ignore it and use some other clock".
leokennis 6y ago
It will not happen. The science is overwhelming that having one timezone all year long is worse for people, and switching the clock back and forth twice a years is a minor nuisance at most. The EU's "Ban DST" is the same populist bullshit as Trumps "inject Windex to cure COVID". Based on nothing and ignorant at best. And the cherry on top is, if you ask the EU if they want to receive a no strings attached gift of €10.000.000.000.000 or €11.000.000.000.000, it would still take them 20 years to decide. No way they will ever reach consensus on DST.
- etripe 6y ago
  If the science is overwhelming, do you have a source? If not, what are the downsides to having the same timezone all year?
  - kenniskrag 6y ago
    Never heard about windex. Now I know.
  - throw0101a 6y ago
    [Some links that I've posted the last few times DST has come up:] The folks who study this: * https://en.wikipedia.org/wiki/Chronobiology https://en.wikipedia.org/wiki/Chronobiology Seem to have come to a consensus that if we're going to get rid of DST, then health-wise it is best to have Standard Time year-round: > As an international organization of scientists dedicated to studying circadian and other biological rhythms, the Society for Research on Biological Rhythms (SRBR) engaged experts in the field to write a Position Paper on the consequences of choosing to live on DST or Standard Time (ST). The authors take the position that, based on comparisons of large populations living in DST or ST or on western versus eastern edges of time zones, the advantages of permanent ST outweigh switching to DST annually or permanently. * https://journals.sagepub.com/doi/full/10.1177/0748730419854197 https://journals.sagepub.com/doi/full/10.1177/07487304198541... For a longer-read, referencing quite a bit of academic literature, but a conclusionary snippet: > In summary, the scientific literature strongly argues against the switching between DST and Standard Time and even more so against adopting DST permanently. The latter would exaggerate all the effects described above /beyond/ the simple extension of DST from approximately 8 months/year to 12 months/year (depending on country) since /body clocks/ are generally even later during winter than during the long photoperiods of summer (with DST) (Kantermann et al., 2007; Hadlow et al., 2014, 2018; Hashizaki et al., 2018). Perennial DST increases SJL prevalence even more, as described above. * https://www.frontiersin.org/articles/10.3389/fphys.2019.00944/full https://www.frontiersin.org/articles/10.3389/fphys.2019.0094... Other position papers that I've dug up over the years when curiosity got the better of me: > Society for Research on Biological Rhythms (SRBR) is dedicated to advancing rigorous, peer-reviewed science and evidence-based policies related to sleep and circadian biology. * https://srbr.org/advocacy/daylight-saving-time-presskit/ https://srbr.org/advocacy/daylight-saving-time-presskit/ * (refs, with pro and con): https://srbr.org/wp-content/uploads/2020/09/DST-References-SRBRPressKit.pdf https://srbr.org/wp-content/uploads/2020/09/DST-References-S... European Sleep Research Society: * https://esrs.eu/wp-content/uploads/2019/03/To_the_EU_Commission_on_DST.pdf https://esrs.eu/wp-content/uploads/2019/03/To_the_EU_Commiss... Canadian Society for Chronobiology: * https://www.theglobeandmail.com/opinion/article-turn-back-the-clock-on-daylight-savings-why-standard-time-all-year/ https://www.theglobeandmail.com/opinion/article-turn-back-th... * https://twitter.com/ChronobioCanada/status/1190632096596926464 https://twitter.com/ChronobioCanada/status/11906320965969264... American Academy of Sleep Medicine (with 36 footnotes if you want to dig further): * https://jcsm.aasm.org/doi/10.5664/jcsm.8780 https://jcsm.aasm.org/doi/10.5664/jcsm.8780 * https://doi.org/10.5664/jcsm.8780 https://doi.org/10.5664/jcsm.8780 The Centre for Chronobiology, based at the Psychiatric University Hospital (University of Basel): * http://www.chronobiology.ch/wp-content/uploads/2019/08/JBR-DST.pdf http://www.chronobiology.ch/wp-content/uploads/2019/08/JBR-D... * http://www.chronobiology.ch http://www.chronobiology.ch (Personally, I'm just going to trust the experts on this as I don't have the energy to go digging in things. A quick cursory Google/DDG search is enough for me.)

jmgao 6y ago

> both The USA and Canada have been toying with the idea of dropping daylight savings time Individual states are toying with the idea as well [1], which presents a problem if one of the tzdata locations decides to change its rules. You're screwed no matter what you choose to do. :-( 1: https://www.syracuse.com/state/2020/11/state-senator-introduces-bill-to-end-daylight-saving-time-in-new-york.html https://www.syracuse.com/state/2020/11/state-senator-introdu...

siculars 6y ago
They already do. See Arizona.
- 1-more 6y ago
  …and then see Navajo reservation in there, and then see the Hopi reservation inside of that!
Izkata 6y ago
It gets worse: DST in Indiana has to be handled on a per-county basis for anything prior to 2006. https://en.m.wikipedia.org/wiki/Time_in_Indiana https://en.m.wikipedia.org/wiki/Time_in_Indiana
- spiralx 6y ago
  It gets worse: from when I had to deal with this some years back IIRC in Saudi Arabia the start and end of DST is set by decree every year.

Lvl999Noob 6y ago

On the topic of DST... can you explain why some countries use DST? Anytime I look for the reasoning of it, it says that DST helps "make better use of daytime" but how? The earth isn't gonna say "Damn! These people changed their clocks. I better change by rotation and give them more sun time." Whether you have DST or not, you still have the same amount of time with sunlight in a day.

macintux 6y ago
Just once I’d like to have a time zone discussion on HN that doesn’t devolve into pages of arguing about daylight saving time. If you search HN you’ll find plenty on this topic.
- db48x 6y ago
  You'll have a happier life if your dreams are attainable.
- klyrs 6y ago
  I mean, you're not wrong... but what else is there to talk about? Fact of the matter is, your preferences depend on where you live, your lifestyle, and the amount of time you spend on date&time fuckery in code. It's a contentious issue.
mabbo 6y ago
Golf courses. Well, okay, this is my wonderful father's half serious answer that I love to retell. The basic idea is that it's easier to convince everyone that is actually 5:00pm and time to leave work than it is to convince just your boss that you want to start work an hour earlier and leave and hour earlier. This problem is then applied to politicians and other powerful people, who want to go golfing after work. If there's no DST, the sun will set "earlier" according to the clock, and you can't get in a full 18 holes. So therefore, we change all the clocks so that powerful rich people can go golfing. No other group of people sees any benefits to DST.
- Lvl999Noob 6y ago

phlo 6y ago

> If you ask for output in EDT, but the date is in December (which is not part of daylight savings time) then should the date output be UTC-4 or UTC-5? EST is always UTC-4 and EDT is always UTC-5. Both of these exist throughout the year. The only change happening in Spring/Autumn is that some places change which time zone they currently observe. This also addresses the second problem that you outlined. As long as the query is properly specified (if you want information related to a location, use America/New York; if you want information related to a time zone, use the time zone), you can always get an unambiguous and correct answer.

throw0101a 6y ago
> EST is always UTC-4 and EDT is always UTC-5. Except you have those reversed. :)
dmm 6y ago
To be pedantic EST and EDT are offsets. America/New_York is the timezone which consists of multiple offsets that depends on the time of year and date mostly determined by the local civil authority. For example in 2005, the US extended daylight saving time by four weeks. This difference between 2004 and 2006 is a part of the timezone.
- phlo 6y ago
  Cool, I hadn't realized that distinction in terminology. Thanks for pointing it out! :)
emmelaich 6y ago
< EST is always UTC-4 Unfortunately not. Australia also used EST until recently. Now they've introduced AEST, but I'm sure there's systems out there using EST.
mikelward 6y ago
When somebody writes EST in summer they mean UTC-4. Interpreting that as UTC-5 is almost always wrong.

kelnos 6y ago

I (living in California) usually use "PST8PDT", which does what I want, all year round (for some irrational reason I refuse to claim that I live in Los_Angeles[0]). I believe there's also "EST5EDT", "CST6CDT", and "MST7MDT" as well. But agree that this is just a grab bag of confusing garbage. [0] I suppose if CA does away with DST (or keeps it permanently), I will have to change...

boulos 6y ago
Huh, your LA note prompted me to say “That’s why I use US/Pacific”. But someone on the internet tells me I’ve been doing it wrong and US/Pacific has been deprecated for years / I’m not supposed to: https://stackoverflow.com/questions/4309030/difference-between-timezones-america-los-angeles-and-us-pacific-and-pst8pdt https://stackoverflow.com/questions/4309030/difference-betwe...

kenneth 6y ago

I just always write ET, PT, MT, CT.