[tz] Ambiguous abbreviations for Australian timezones when daylight savings is in affect

Russ Allbery rra at stanford.edu
Tue Apr 2 17:50:01 UTC 2013

"Clive D.W. Feather" <clive at davros.org> writes:
> Russ Allbery said:

>> You *definitely* do not want to use time zone abbreviations for this,
>> since they too would be completely wrong for the same reason!  If you
>> schedule a meeting in PDT, you want it to change to PST when daylight
>> saving time ends.  Which is the behavior you get from
>> America/Los_Angeles (or some equivalent identifier such as PST8PDT).

> Except, if I understand correctly, the US terminology "PT" (and
> similarly "ET", "CT", and "MT") means "PST or PDT, whichever is
> currently in force").

It is common to give times in "Eastern" or "Pacific", which means
America/Los_Angeles or America/New_York.  "Central" is sometimes used;
"Mountain" is relatively rare when giving times (at least in my
experience, but I don't live in that zone or near the border of it).  It
*is* common to refer to "mountain time" or "central time" when talking
about time zones informally.  Eastern and Pacific are common when giving
times because that's how TV schedules are done; many channels run two
schedules, one for Eastern and one for Pacific, and people in Central and
Mountain just cope and know to add or subtract an hour from posted
national times.

I don't recall seeing those specific abbreviations as opposed to just the
words, but I doubt I would have paid much attention.  I bet they're used
for things like sports listings for live sporting events.

None of this deals with Arizona particularly well.  :)  I suspect people
in Arizona view themselves as switching between Pacific and Mountain
depending on the time of the year.

Regardless, though, the actual abbreviations used in tzname, etc., aren't
useful for giving the times of recurring meetings.  TZ identifiers (which
include US/Pacific, US/Eastern, etc.) certainly are.

Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>

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