Acronyms for Australian Time Zone Seasons

Paul Eggert eggert at CS.UCLA.EDU
Wed Jan 24 07:52:33 UTC 2007

"Sean B. Durkin" <sean at> writes:

> Even when the context of Australia is known, EST/EST makes it impractical
> to record times in the local clock with the acronym.


> To be consistent with the treatment of other timezones, we should go
> with the closest thing to the official acronym, rather than the most popular
> one.  I acknowledge that there is no legislatively official acronyms,

That may be, but there is at least one legislatively official phrase
that uses "summer time" rather than "daylight time", so it'd be a bit
odd for us to use an acronym ending in "DT".  See the South Australian
Daylight Saving Regulations 2006
which says that it's called "South Australian summer time".

Presumably the corresponding acronym would be "SAST".  But nobody uses
"SAST".  The only reference I can find to "SAST" was
where Glen Turner notes this exact situation and basically says nobody
uses "SAST".

I'm not sure I'd use the Bureau of Metrology as an authority in this
particular matter.  Among other things
bluntly states "The Bureau of Meteorology does not have responsibility
for managing Daylight Saving Time."

What a mess, huh?

I do sense that Australians may be drifting towards the AEST/AEDT
style abbreviations, at least in Internet documents.  See, for

Also, the Google query "ACDT" has about 50,800 hits,
apparently because's style guide now says to use
"ACDT".  In contrast, the query "CDT" has about 26,400
hits and "CST" has about 29,500 hits.  So at least the
federal government seems to somewhat prefer the ACDT abbreviation.
This could well just be due to the style guide at one government news
site, though, so I'm not inclined to say this survey is definitive.

If Australians are actually switching to AEST/AEDT, at some point
we'll probably have to change the tz database.  Not at all sure it's
there yet, though.  The last time I suggested such a change, it was
pretty controversial.

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