Edit report at https://bugs.php.net/bug.php?id=63777&edit=1
ID: 63777
Comment by: kavi at postpro dot net
Reported by: kavi at postpro dot net
Summary: DateTime obj in Dec 2012 in Australia/South TZ
reports 'CST' time zone abbrev
Status: Not a bug
Type: Bug
Package: Date/time related
Operating System: OS X, CentOS, Debian
PHP Version: Irrelevant
Block user comment: N
Private report: N
New Comment:
Here's an interesting one which states CST for both summer and winter:
http://www.travelmath.com/time-zone/Australia/Adelaide
Another site claiming DST is in effect:
http://www.timezoneconverter.com/cgi-bin/zoneinfo.tzc?tz=Australia/Adelaide
So, my main question still being, if 'CST' is 'Central Summer (aka daylight
savings) Time,' then what is 'CDT?'
I'm happy to try to figure out where to take my irritating questions directly
to IANA, BTW, if this is a) indeed a problem and b) solely an upstream problem
as it appears to be.
Previous Comments:
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[2013-01-07 19:32:20] der...@php.net
Olson uses CST the year round:
derick@whisky:~ $ zdump -v -c 2012,2014 Australia/Adelaide
Australia/Adelaide -9223372036854775808 = NULL
Australia/Adelaide -9223372036854689408 = NULL
Australia/Adelaide Sat Mar 31 16:29:59 2012 UTC = Sun Apr 1 02:59:59 2012 CST
isdst=1 gmtoff=37800
Australia/Adelaide Sat Mar 31 16:30:00 2012 UTC = Sun Apr 1 02:00:00 2012 CST
isdst=0 gmtoff=34200
Australia/Adelaide Sat Oct 6 16:29:59 2012 UTC = Sun Oct 7 01:59:59 2012 CST
isdst=0 gmtoff=34200
Australia/Adelaide Sat Oct 6 16:30:00 2012 UTC = Sun Oct 7 03:00:00 2012 CST
isdst=1 gmtoff=37800
Australia/Adelaide Sat Apr 6 16:29:59 2013 UTC = Sun Apr 7 02:59:59 2013 CST
isdst=1 gmtoff=37800
Australia/Adelaide Sat Apr 6 16:30:00 2013 UTC = Sun Apr 7 02:00:00 2013 CST
isdst=0 gmtoff=34200
Australia/Adelaide Sat Oct 5 16:29:59 2013 UTC = Sun Oct 6 01:59:59 2013 CST
isdst=0 gmtoff=34200
Australia/Adelaide Sat Oct 5 16:30:00 2013 UTC = Sun Oct 6 03:00:00 2013 CST
isdst=1 gmtoff=37800
Australia/Adelaide 9223372036854689407 = NULL
Australia/Adelaide 9223372036854775807 = NULL
The S stands for both Standard and Summer (sadly).
------------------------------------------------------------------------
[2013-01-07 19:24:13] kavi at postpro dot net
As you point out from the timeanddate.com site, DST in Australia/South
(Adelaide being the city I use for inquiry) ENDS April 2013, which means it
started in October 2012. So it's currently daylight (not standard) time, is
what I'm saying. It's either me misunderstanding the abbreviation, a bug (in
Olson?) or a bug in my coffee consumption in *my* current time zone, because I
don't understand.
If it's something obvious I apologize for taking folks' time.
------------------------------------------------------------------------
[2013-01-07 19:18:36] ras...@php.net
Ok, it is truly not a bug. According to Olson it is CST in Adelaide now.
Google,
Wolfram and PHP are all in agreement here. Even that timeanddate.com page
states
right on it that:
DST ends on Sunday, April 7, 2013 at 3:00 AM local daylight time
DST starts on Sunday, October 6, 2013 at 2:00 AM local standard time
So surely they should be showing DST right now. The 'S' is supposed to standard
for "Standard" but people tend to use "Summer" as well.
------------------------------------------------------------------------
[2013-01-07 19:07:45] kavi at postpro dot net
Forget the prefix (ACDT vs CDT) portion. Mirroring Olson is good.
If it's summer time in Australia, what does the 'D' in Australian CDT stand for?
The reason I bring this up is because I've researched online and there are a
number of timekeeping and other sites which are in disagreement.
>From http://en.wikipedia.org/wiki/Time_in_Australia
"The main DST zones are the following:
(Australian) Central Daylight Time (CDT or ACDT) â UTC+10:30, in South
Australia
(Australian) Eastern Daylight Time (EDT or AEDT) â UTC+11, in New South
Wales, the A.C.T., Victoria, and Tasmania.
[...]
Beginning in 2008, the start of DST in these states and in South Australia
occurs on the first Sunday in October, and its end is on the first Sunday in
April."
According to this, DST-observing zones in Australia are currently observing DST
during the Australian summer (whether it's called summer time or not) - so
unless I have the meanings of 'S' and 'D' in CST/CDT incorrect, or I've
otherwise reasoned incorrectly, this is still a bug.
According to Wolfram Alpha (Checked just now, 7 January 2013) it is CST right
now: https://www.wolframalpha.com/input/?i=current+time+in+Adelaide
According to timeanddate.com (on 7 January 2013) it is CDT right now:
http://www.timeanddate.com/worldclock/city.html?n=5
This does need attention, even if only to verify that it is truly not a bug.
------------------------------------------------------------------------
[2012-12-17 01:35:44] ahar...@php.net
Unfortunately, as a Western Australian who's suffered through our state
government's various flip-flops on daylight saving, I'm much more familiar with
this than I want to be â the Olson database is technically correct here, as
every state legislates or proclaims daylight saving time as "summer time", so
the S part of the CST abbreviation is correct. Beyond that, I think that the
Olson notes and related mailing list posts lay out the case for not prefixing
the abbreviations reasonably well.
Realistically, any change to this would need to happen upstream anyway â I
doubt we want to start patching tzdata to differ from the mainline that almost
everyone else deploys.
------------------------------------------------------------------------
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