[tz] Australian Time Zone Abbreviations Discussion Review

Shaun Bouckaert shaun.bouckaert at gmail.com
Mon Mar 5 08:10:33 UTC 2012

I started a discussion on this mailing list in November 2011 in
regards to the incorrect time zone abbreviations used for Australian
time zones. Initially there were several responses, the majority of
which were positive to change, and yet the conversation seems to have
died off.

Recently published on this list was the IETF RFC 6557 "Procedures for
Maintaining the Time Zone Database". The relevant section of that
document to this discussion, Section 3 "Making Updates to the TZ
Database" specifies at the bottom "To be clear, the TZ Coordinator
SHALL NOT set time zone policy for a region but use judgement and
whatever available sources exist to assess what the average person on
street would think the time actually is, or in case of historical
corrections, was." Also, point 3.3 states "Changes to existing entries
SHALL reflect the consensus on the ground in the region covered by
that entry."

There were several people involved in the discussion that took place:

Myself (Shaun Bouckaert <shaun.bouckaert at gmail.com>)
Edwin Groothuis <edwin at mavetju.org>
Eric Ulevik <eulevik at gmail.com>
Elliot Lear <lear at cisco.com>
Greg Black <gjb at yaxom.com>

I reside in Australia, however I am not aware of the nationality or
residency of any of the other contributors. I will summarise my points
then attempt to do so with the points made by others. It is not my
intention to mislead and if my summaries of their contributions are
inaccurate then I hope they will correct me. Their contributions to
the original discussion are available to view.

I originally started the discussion after finding the Australian
Federal Government had a web page of information regarding time zones
in Australia. This can be accessed at

This lists the timezones as

Australian Eastern Standard Time: UTC +10 hours abbreviated as AEST
Australian Central Standard Time: UTC +9 ½ hours abbreviated as ACST
Australian Western Standard Time: UTC +8 hours abbreviated as AWST

Where daylight savings is concerned, NSW, ACT, Victoria and Tasmania
move from AEST to Australian Eastern Daylight Time UTC +11 hours
abbreviated as AEDT
SA and Broken Hill in NSW move from ACST to Australian Central
Daylight Time UTC +10 ½ hours abbreviated as ACDT

After this initial posting Edwin replied with his support. Eric then
replied stating that Time Zones are legislated at the state level, not
the federal level, seeming to imply that only state law should matter.
Considering the RFC specifically states that the time zone policy
should be based on available sources to assess what the average person
on the street would think, and the fact that state legislation doesn't
specify an abbreviation, there's no reason that this federal
government information, which accurately reflects what everyone I have
discussed this matter with understands to be true, should be
discounted. This was reenforced by Edwin who pointed out two ways
forward, stay where we are based on the absence of any specification
of abbreviations in state legislation and continue bickering on this
issue or move forward with the clearly defined federal information
that fixes ambiguity that exists on an international level with the
existing abbreviations and hopefully stop the bickering.

Elliot then put forward two points, the first in line with the now
existing guidelines in regards to what people on the street think, and
the second point being to taking caution to possible side effects that
could be caused by changing this. He points out that we could be going
from ambiguous labels to something that is also ambiguous, but is
there a way of finding out if the AEST, ACST, etc. are ambiguous in
any way? Considering the significance of EST and CST to North America,
it certainly seems more significant to reduce the ambiguity there.

Edwin then found several Australian organisations and reviewed what they use.

The ABC (National Broadcaster): AEST
Channel 10: Mostly AEST, some instances of EST

News Organisations:
Sydney Morning Herald: EST
The Australian: AEST
The Daily Telegraph: Both EST and AEST

Government Organisations:
The Australian Bureau of Meteorology: Uses both, but specifies using
AEST in their submission guidelines.

Appended to this list I can add the Queensland Department of Transport
and Main Roads, which I found is using AEST in their website Terms of

I also pointed out at the time that many instances of the use of EST
could easily be due to the current state of the TZ database and would
likely be corrected to AEST (or other where appropriate) with the
update to the TZ database. It was also pointed out that Australians
would on large understand the use of the A prefixed abbreviations due
to their widespread use, especially by major broadcasters and news

Greg Black added that he received three emails from different
Australian organisations that used ADST for a timezone that he would
personally label AEDT. I do not see this being an argument against the
change, but indeed an argument for. There is existing confusion, some
of it due to the incorrect labels in the TZ database. The fact that
the federal government has presented a source for this change means
that there's significant grounds for using it as a correct version or

Of the 5 people mailing the list during this discussion, the most
significant contributions were made by myself and Edwin, both of us in
support of the change to the A prefix, which also seemed to be
supported by Greg Black who said he would personally label the
timezone that the ADST label had referred to as AEDT.

I could find no arguments put forward that demonstrated any advantage
of the current system over the proposed alternative besides
maintaining the status quo. I respect the caution put towards
unintended side effects, but where these are due to corrections on
what is arguably wrong information, isn't it better to fix it sooner
rather than later?

Shaun Bouckaert

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