On Thu, 30 Jul 2026 at 14:51, James Bellaire via tz <[email protected]> wrote:
> I don't consider nor expect "-04" to be common use for the eastern US or > "-07" to be common use for western Canada. It wouldn't be; rather, if we end up using these numeric abbreviations in our data, it would be to signal that no common abbreviation exists any longer, which is a somewhat more likely scenario given how the proposed changes would disrupt the traditional North American nomenclature. (Specifically, more colloquial abbreviations like "ET" could mean entirely different things in the US vs in Canada, depending on the time of year, while each country could end up using different names for the same offset.) I can see having %z or an explicit "-04" style format to see if that > breaks more systems than an EST that does not equal -05 As I said near the top of the thread relaying that this bill had passed the House, no matter what we do, *someone's* assumptions will break. https://lists.iana.org/hyperkitty/list/[email protected]/message/O6WINCUDYOW3T37QAEDFDCTSUJQSJH3R/ Arguably, there are situations in which it can be better to make that breakage clear in an intentionally minimally disruptive way. Using "xST" would just paper over the problem in one way, and using "xDT" would paper over it in another way. but I hope that > the format field would change back to EST once software can handle the > legislated time zone (assuming EST is ever legislated as being -04). > To be clear, this bill *does* legislate as such, within the US. But not elsewhere. And that complication, tied together with the unique history of these North American abbreviations and their legacy uses in software, makes changing their meaning more difficult than it would be for others. But in any case, our goals with abbreviations are less about legislated names and more about actual common usage (anticipated whenever possible, observed otherwise). So just because we may not have a good answer now doesn't mean we never will. And who knows… if this goes forward but then is swiftly rolled back like the last such experiment, maybe "xDT" will have retroactively been the right answer all along. -- Tim Parenti
