Updated Australian time zone names/strings

Paul Eggert eggert at twinsun.com
Thu Apr 5 17:03:45 UTC 2001

> Date: Thu, 5 Apr 2001 23:59:40 +1000 (EST)
> From: David J N Begley <d.begley at uws.edu.au>
> since my last question everything has gone quiet:

There has been some activity recently.  Let me try to summarize my
understanding of the discussion.  I'm not Australian, so everything I
write should be taken as comments by an interested outsider who does
not entirely understand the situation there.

I see the following points of dispute:

* How important are unique time zone abbreviations?

  Here I tend to agree with the point (most recently made by Chris
  Newman) that unique abbreviations should not be essential for proper
  operation of software.  We have other instances of ambiguity
  (e.g. "IST" denoting both "Israel Standard Time" and "Indian
  Standard Time"), and they are not likely to go away any time soon.
  In the old days, some software mistakenly relied on unique
  abbreviations, but this is becoming less true with time, and I don't
  think it's that important to cater to such software these days.

  On the other hand, there is another motivation for unambiguous
  abbreviations: it cuts down on human confusion.  This is
  particularly true for Australia, where "EST" can mean one thing for
  time T and a different thing for time T plus 1 second.

* Does the relevant legislation indicate which abbreviations should be used?

  Here I tend to think that things are a mess, just as they are in
  many other countries.  We Americans are currently disagreeing about
  which abbreviation to use for the newly legislated Chamorro Standard
  Time, for example.

  Personally, I would prefer to use common practice; I would like to
  refer to legislation only for examples of common practice, or as a

* Do Australians more often use "Eastern Daylight Time" or "Eastern
  Summer Time"?  Do they typically prefix the time zone names with
  the word "Australian"?

  My own impression is that both "Daylight Time" and "Summer Time" are
  common and are widely understood, but that "Summer Time" is more
  popular; and that the leading "A" is also common but is omitted more
  often than not.  I just used AltaVista advanced search and got the
  following count of page hits:

   1,103 "Eastern Summer Time" AND domain:au
     971 "Australian Eastern Summer Time" AND domain:au
     613 "Eastern Daylight Time" AND domain:au
     127 "Australian Eastern Daylight Time" AND domain:au

  Here "Summer" seems quite a bit more popular than "Daylight",
  particularly when we know the time zone is Australian and not US,
  say.  The "Australian" prefix seems to be popular for Eastern Summer
  Time, but unpopular for Eastern Daylight Time.

  For abbreviations, tools like AltaVista are less useful because of
  ambiguity.  Many hits are not really time zones, unfortunately, and
  many hits denote US time zones and not Australian ones.  But here
  are the hit counts anyway:

  161,304 "EST" and domain:au
   25,156 "EDT" and domain:au
   18,263 "AEST" and domain:au
   10,416 "AEDT" and domain:au
   14,538 "CST" and domain:au
    5,728 "CDT" and domain:au
      176 "ACST" and domain:au
       29 "ACDT" and domain:au
    7,539 "WST" and domain:au
       68 "AWST" and domain:au
  This data suggest that Australians tend to omit the "A" prefix in
  practice.  The situation for "ST" versus "DT" is less clear, given
  the ambiguities involved.

* How do Australians feel about the abbreviations in the tz database?

  If you just count Australians on this list, I count 2 in favor and 3
  against.  One of the "against" votes (David Keegel) counseled delay,
  saying that both AEST/AEDT and EST/EST are widely used and
  understood in Australia.

>   So, what happens now?

The final decision is Arthur David Olson's, since he's maintaining
the database.  My own mild preference for now (given what's been said
so far) would be to leave it alone.

More information about the tz mailing list