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Comment by rlpb

5 months ago

The timezone names are defined by the Olson database, not Debian. It is the only sensible system in our ecosystem. It certainly beats Outlook which still wrongly insists that my timezone is GMT just because I live in the UK and still confuses everyone (it isn't during the summer; we use BST over the summer, not GMT).

> It is the only sensible system in our ecosystem. It certainly beats Outlook which still wrongly insists that my timezone is GMT just because I live in the UK and still confuses everyone (it isn't during the summer; we use BST over the summer, not GMT).

I went to both Outlook and Teams to check and I have the option to select both "(UTC) Universal Coordinated Time" and "(UTC+0) Dublin, Edinburgh, Lisbon, London", with the later adapting to changes in the summer; but I do agree it's clunkier than the Olson database, combining multiple regions in a single option while splitting regions with the same timezone rules into different ones.

  • > ...I have the option to select..."(UTC+0) Dublin, Edinburgh, Lisbon, London"

    This is factually wrong already. In summer, London is not UTC+0. They mean "UTC+0 ignoring DST", but that is not useful. If they're going to be specific by specifying a UTC offset, what's the point if it doesn't include DST? How is that useful as an identifier when it's ambiguous? With their history of getting it wrong, this just introduces doubt about its correctness.

    Further, if you ask Outlook to show you two timezones at once and do not override labels, it will label BST "UTC+0" (it isn't; it's UTC+1!) while also calling eg. India "UTC+5:30", implying a time difference of 5.5 hours when it is actually 4.5 hours. This isn't just a case of "ah - they actually mean ..."; it's most definitely wrong!

    The problem is that it has a very US-centric view of what DST is. You can mostly ignore it in the US when calculating time zones because the entire country changes DST at the same time. This is not the case internationally.

    • > This is factually wrong already. In summer, London is not UTC+0.

      Yeah, the "regular" time is UTC+0, with it changing in the summer. I'm aware it's a really poor implementation, but it is there as a separate option from "UTC" itself preserving the same offset (0) all year.

      > The problem is that it has a very US-centric view of what DST is. You can mostly ignore it in the US when calculating time zones because the entire country changes DST at the same time. This is not the case internationally.

      Probably the reason they, for some reason, split the setting for "Amsterdam, Bern, Berlin, Rome, Stockholm, Vienna" and "Brussels, Copenhaguen, Madrid, Paris" even though they all follow the same timezone and change simultaneously.

    • > In summer, London is not UTC+0. They mean "UTC+0 ignoring DST", but that is not useful

      This is how 99% of people interpret it

      It's not ambiguous as you imply.

      Summer time is not the default time

      I don't know enough about the India case to know how/why it's wrong though

      3 replies →

Any moderately reasonable system would be backwards compatible and/or migrate existing values

> The worst part about this is that it didn't get so much as a mention in the Debian 13 release notes. I read through that document before going for it and never encountered it. Indeed, even now, you won't find "tzdata" or "zone" in it.

  • > Any moderately reasonable system would be backwards compatible

    It is. Install: tzdata-legacy