From: tz <tz-bounces@iana.org> On Behalf Of Paul.Koning@dell.com
On Mar 5, 2020, at 8:45 PM, Paul Eggert <eggert@cs.ucla.edu> wrote:
[EXTERNAL EMAIL] On 3/5/20 5:31 PM, Paul Goyette wrote:
Doesn't such a position, however, fly in the face of the "boots on the ground" approach we've taken in other situations?
Yes it does. But then, we consistently flew in the face of that approach in the past when this situation arose, so at least we'd be *consistently* inconsistent. (There is a technical obstacle to having a time zone observe DST indefinitely, as this can't be implemented via POSIX TZ strings on many platforms.)
Another possibility would be to put "-07" into the database for now, until we find out what abbreviation (if any) people actually use once the timestamps diverge in November. If people end up using "PDT" next winter in Yukon we can put that into the database, even though it will be odd that it's "PDT" even though the is_dst flag will be 0 due to the abovementioned technical obstacle.
I've been fearing this technical snafu for many months as the "permanent DST" movement has gained steam in North America.
I view isdst as valid only if there are two time offsets, active at different times according to something resembling a rule. Normally "isdst" means summer time, with one or two oddball exceptions. But when only one rule is in effect year-round, it doesn't make sense to set the "non-standard" flag, which is what "isdst" is.
So never mind the "technical obstacle"; set is_dst 0 as a matter of principle no matter whether POSIX justifies it or not.
I think everyone is in agreement on setting is_dst to 0. Good. I don't agree with the idea of using "-07" as the time zone abbreviation with a "wait and see" approach. I fear it would lead to legibility problems in such places as weather forecasts. E.g. notice how the current time zone abbreviation is prominently displayed in a time stamp on Environment Canada's weather forecast pages for Dawson City YT and Fort Nelson BC. https://weather.gc.ca/city/pages/yt-6_metric_e.html https://weather.gc.ca/city/pages/bc-83_metric_e.html. I would be very surprised if these pages did not pull the time zone abbreviations directly from tzdata time zone files. The current time stamp of "8:00 PM MST Thursday 5 March 2020" is very clear and very readable. If the same time stamp were to show up as "8:00 PM -07 Thursday 5 March 2020", I would consider it to be confusing to the average Canadian. And I still don't agree with the idea of using "PDT" even though it would align with the Yukon government's press release. We have to consider that: America/Dawson_Creek, America/Fort_Nelson, America/Whitehorse, and America/Dawson together form a contiguous area within a single country (Canada). Starting next Sunday, the entire area will be on permanent UTC-7. America/Dawson_Creek has been using the MST time zone abbreviation since 1972. America/Fort_Nelson has been using the "MST" time zone abbreviation since 2015. It would make no sense at all to apply a different time zone abbreviation (either "-07" or "PDT") to America/Dawson or America/Whitehorse; doing so would create a permanent confusion and inconsistency that would never go away. If we stick with "MST" there may be a few people that are confused for a few days, but that confusion will quickly pass. -chris