Australian time zone abbreviations

Paul Eggert eggert at CS.UCLA.EDU
Thu Jun 1 22:55:01 UTC 2006

Chuck Soper <chucks2 at> writes:

> Should the current official time zone abbreviations be used rather
> than the popular ones?

That could be.  I reran the AltaVista queries that I used on
2001-04-05 (and documented in "australasia") and got quite different
results this time:

         548 "Eastern Summer Time" AND domain:au
         181 "Australian Eastern Summer Time" AND domain:au
      10,200 "Eastern Daylight Time" AND domain:au
       3,740 "Australian Eastern Daylight Time" AND domain:au

   2,130,000 "EST" and domain:au
     133,000 "EDT" and domain:au
   7,070,000 "AEST" and domain:au
   1,900,000 "AEDT" and domain:au

     161,000 "CST" and domain:au
      26,100 "CDT" and domain:au
     482,000 "ACST" and domain:au
     265,000 "ACDT" and domain:au

     153,000 "WST" and domain:au
     545,000 "AWST" and domain:au

To double check this I ran similar queries on Google, and got
the following approximate hit counts:

     216,000 "Eastern Summer Time"
     228,000 "Australian Eastern Summer Time"
     105,000 "Eastern Daylight Time"
      97,800 "Australian Eastern Daylight Time"

   7,730,000 "EST"
     353,000 "EDT"
  15,600,000 "AEST"
   1,440,000 "AEDT"

     433,000 "CST"
      48,100 "CDT"
     488,000 "ACST"
     372,000 "ACDT"

     600,000 "WST"
     495,000 "WST"

This indicates that (on the web, at least) there's been a decisive
shift from "summer time" to "daylight time" in Australia, and a shift
from abbreviations like "EST" or "EST/EDT" to abbreviations like

Would any other Australians care to chime in on this?  Is there a
sense that the American-style time zone terminology has taken over
from the British in the last five years?

> Perhaps, the older tz abbreviations without the "A" for Australia
> could be maintained for dates in the past similar to using PWT
> (Pacific Wartime) for Pacific Time?

The PWT/PDT transition is easy, since it's just the end of the war.
But as far as I know switching from EST to AEST would be tricky, since
there's no specific point at which the switchover could be said to
have occurred.  Unless there's some official time stamp somewhere
(some law or regulation establishing the abbreviations, perhaps?).

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