[tz] Please remove ambiguous time zone abreviations for Australia [SEC=UNCLASSIFIED]

Timothy Arceri T.Arceri at bom.gov.au
Mon Apr 8 01:14:01 UTC 2013

To further expand on Roberts search results. If you take a closer look at the only result that would support the status quo "34,900: "Eastern Summer Time (EST)" almost every result in the first 10 pages comes from
http://www.theweatherchaser.com e.g http://www.theweatherchaser.com/radar-loop/IDR023-melbourne where the page states:

*  UTC is Australian Eastern Summer Time (EST) -11 hours (Daylight Savings).
*  UTC is Australian Eastern Daylight Time (EDT) -10 hours.

This is incorrect whether you use Australian Eastern Summer Time or Australian Eastern Daylight Time they are both 11 hours (Daylight Savings) so none of the results from www.theweatherchaser.com<http://www.theweatherchaser.com> should be considered valid as the maintainer has clearly no understanding of the timezone references.
So if we now do a new search we get:

9: "Eastern Summer Time EST" -site:theweatherchaser.com

From: tz-bounces at iana.org [mailto:tz-bounces at iana.org] On Behalf Of Robert Greenwood
Sent: Monday, 8 April 2013 9:52 AM
To: 'tz at iana.org'
Subject: [tz] Please remove ambiguous time zone abreviations for Australia [SEC=UNCLASSIFIED]

Hi all,
I know this might sound like a broken record to some, but could we please remove ambiguous time zone abreviations for Australia? I can't for the life of me understand why anyone would want to keep the Australian zones as EST/EST and CST/CST rather than EST/EDT and CST/CDT or AEST/AEDT and ACST/ACDT.

Stating that there in no need to change it is nonsensical. It is obvious that using the abbreviation Eastern Standard Time (EST) and Eastern Summer Time (EST) is useless at best. The fact that if you have time zones you need them to be unambiguous is self evident, otherwise why have them.

Stating that there are conflicting messages from state and federal government regarding the use of time zones in Australia is misleading. No State or federal government proposes the use of EST/EST and CST/CST as the correct usage of time zone abbreviations. Whilst there is some inconsistency in the usage of AEDT/EDT/EDST within those sites when they explicitly state which time zone should be used it is AEST/AEDT and ACST/ACDT.

Finally, the arguments around the usage of Eastern/Central Summer Time (EST/CST) being the status Quo amongst Australians based off the survey conducted in the following linked is flawed:


searching for EDT or EST by themselves will return a number of things that have no relation to time zones. Similarly, "Eastern Summer Time" and "Eastern Daylight Time" do not necessarily relate to the usage of a particular abbreviation.

Searching for the number of hits for the following strings gives a better understanding of the usage of the relevant time zone acronyms in Australia:
Google results for au domain:

45,100: "Eastern Standard Time (EST)"
82,400: "Eastern Standard Time (AEST)"

34,900: "Eastern Summer Time (EST)"
117: "Eastern Summer Time (AEST)"
72,100: "Eastern Daylight Time (EDT)"
218,000: "Eastern Daylight Time (AEDT)"

387,000: "Central Standard Time (CST)"
8,030: "Central Standard Time (ACST)"

3: "Central Summer Time (CST)"
3: "Central Summer Time (ACST)"
22,300: "Central Daylight Time (CDT)"
1,460: "Central Daylight Time (ACDT)"

Here we are only looking at cases where the time zone abbreviation has been defined. These results show that the abbreviation for Daylight time EDT/AEDT/CDT/ACDT is overwhelmingly greater than the usage of the abbreviation for Summer time EST/AEST/CST/ACST. Furthermore, varients of the search for "Eastern Daylight Saving/s Time (A/EDT)" give another ~3,000 hits and variants of "Eastern Daylight Saving/s Time (A/EDST)" only give ~ 500 results.
However, a cursory glance still shows that many of these results are not related to Australia. So this method is still flawed but I cannot think of a better way of searching for the status Quo.
Please change the time zone abbreviations in Australia to EST/EDT and CST/CDT or AEST/AEDT and ACST/ACDT.
Dr Robert Greenwood | Tsunami Modelling Support
National Meteorological and Oceanographic Centre
Bureau of Meteorology
GPO Box 1289 Melbourne VIC 3001
Level 11, 700 Collins Street, Docklands VIC 3008
Tel: +61 3 9616 8455 | r.greenwood at bom.gov.au<mailto:r.greenwood at bom.gov.au>

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