Fwd: [IANA #636310] how to check a time
Hello, Can you point me in the direction of where I can double check that IANA has the correct time for New Zealand? I am worried that IANA has the wrong time for New Zealand, as Google Calendar which claims to use IANA Time Zone Database, displays the incorrect time for New Zealand. It displays GMT + 12 Auckland but it should be GMT + 13 Auckland, as we are observing Daylight Savings time. Sorry I could not find the right place to check this on your website - can you please check for me or tell me where I can check what time the IANA Time Zone Database has for New Zealand? I will let Google know if the mistake lies with them. Thanks Gemma Begin forwarded message:
From: Paul Eggert <eggert@cs.ucla.edu> Date: 29 November 2012 2:17:18 PM NZDT To: Gemma Conn <gemma@biozone.co.nz> Subject: Re: Fwd: [IANA #636310] how to check a time
On 11/28/2012 12:49 PM, Gemma Conn wrote:
I couldn't find the place on the IANA website where I can check a time...
I'm afraid there isn't a simple way to do that automatically. I suggest you ask by sending email to tz@iana.org. This mailing list is discussed in <http://www.iana.org/time-zones>.
On Thu, 29 Nov 2012, Gemma Conn wrote:
Can you point me in the direction of where I can double check that IANA has the correct time for New Zealand? I am worried that IANA has the wrong time for New Zealand, as Google Calendar which claims to use IANA Time Zone Database, displays the incorrect time for New Zealand. It displays GMT + 12 Auckland but it should be GMT + 13 Auckland, as we are observing Daylight Savings time.
Looks okay: Pacific/Auckland Sat Sep 29 14:00:00 2012 UTC = Sun Sep 30 03:00:00 2012 NZDT isdst=1 gmtoff=46800 Pacific/Auckland Sat Apr 6 13:59:59 2013 UTC = Sun Apr 7 02:59:59 2013 NZDT isdst=1 gmtoff=46800 46800 / 3600 = 13 cheers, Derick
The initial question of this thread implies that there is a need for a non-programmer's window into the IANA Time Zone Database. May I therefore suggest taking a look at Time.is, which has the time for 7 million locations around the world, and usually runs the latest version of the IANA Time Zone Database. The currently installed version is specified near the bottom of http://time.is/about Sincerely, Even Scharning Time.is - exact time, any time zone http://time.is/ On Thu, 29 Nov 2012, Gemma Conn wrote:
Can you point me in the direction of where I can double check that IANA has the correct time for New Zealand? I am worried that IANA has the wrong time for New Zealand, as Google Calendar which claims to use IANA Time Zone Database, displays the incorrect time for New Zealand. It displays GMT + 12 Auckland but it should be GMT + 13 Auckland, as we are observing Daylight Savings time.
On Nov 28, 2012, at 5:28 PM, Gemma Conn <gemma@biozone.co.nz> wrote:
Hello,
Can you point me in the direction of where I can double check that IANA has the correct time for New Zealand?
Go to http://www.iana.org/time-zones download the latest version of the time zone data (and possibly download the latest version of the time zone code and read the zic.8.txt file for a description of the time zone data file), and then check what the time zone data file "australasia" says about New Zealand. What tzdata2012j's australasia file says is: ############################################################################### # New Zealand # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule NZ 1927 only - Nov 6 2:00 1:00 S Rule NZ 1928 only - Mar 4 2:00 0 M Rule NZ 1928 1933 - Oct Sun>=8 2:00 0:30 S Rule NZ 1929 1933 - Mar Sun>=15 2:00 0 M Rule NZ 1934 1940 - Apr lastSun 2:00 0 M Rule NZ 1934 1940 - Sep lastSun 2:00 0:30 S Rule NZ 1946 only - Jan 1 0:00 0 S # Since 1957 Chatham has been 45 minutes ahead of NZ, but there's no # convenient notation for this so we must duplicate the Rule lines. Rule NZ 1974 only - Nov Sun>=1 2:00s 1:00 D Rule Chatham 1974 only - Nov Sun>=1 2:45s 1:00 D Rule NZ 1975 only - Feb lastSun 2:00s 0 S Rule Chatham 1975 only - Feb lastSun 2:45s 0 S Rule NZ 1975 1988 - Oct lastSun 2:00s 1:00 D Rule Chatham 1975 1988 - Oct lastSun 2:45s 1:00 D Rule NZ 1976 1989 - Mar Sun>=1 2:00s 0 S Rule Chatham 1976 1989 - Mar Sun>=1 2:45s 0 S Rule NZ 1989 only - Oct Sun>=8 2:00s 1:00 D Rule Chatham 1989 only - Oct Sun>=8 2:45s 1:00 D Rule NZ 1990 2006 - Oct Sun>=1 2:00s 1:00 D Rule Chatham 1990 2006 - Oct Sun>=1 2:45s 1:00 D Rule NZ 1990 2007 - Mar Sun>=15 2:00s 0 S Rule Chatham 1990 2007 - Mar Sun>=15 2:45s 0 S Rule NZ 2007 max - Sep lastSun 2:00s 1:00 D Rule Chatham 2007 max - Sep lastSun 2:45s 1:00 D Rule NZ 2008 max - Apr Sun>=1 2:00s 0 S Rule Chatham 2008 max - Apr Sun>=1 2:45s 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Pacific/Auckland 11:39:04 - LMT 1868 Nov 2 11:30 NZ NZ%sT 1946 Jan 1 12:00 NZ NZ%sT Zone Pacific/Chatham 12:13:48 - LMT 1957 Jan 1 12:45 Chatham CHA%sT # Auckland Is # uninhabited; Maori and Moriori, colonial settlers, pastoralists, sealers, # and scientific personnel have wintered # Campbell I # minor whaling stations operated 1909/1914 # scientific station operated 1941/1995; # previously whalers, sealers, pastoralists, and scientific personnel wintered # was probably like Pacific/Auckland ###############################################################################
I am worried that IANA has the wrong time for New Zealand, as Google Calendar which claims to use IANA Time Zone Database, displays the incorrect time for New Zealand. It displays GMT + 12 Auckland but it should be GMT + 13 Auckland, as we are observing Daylight Savings time.
The rules that apply currently are: Rule NZ 2007 max - Sep lastSun 2:00s 1:00 D and Rule NZ 2008 max - Apr Sun>=1 2:00s 0 S which say that Daylight Savings Time starts on the last Sunday in September at 2:00 standard time, shifting by one hour, and ends on the first Sunday in April at 2:00 standard time (3:00 DST). If the calendar is correctly set to honor the New Zealand DST rules, this would seem to indicate that either 1) whatever Google Calendar is using isn't the IANA time zone database or 2) they're not using it correctly or 3) they think the last Sunday in September 2012 hasn't happened yet.
All you need is an up to date Unix system, then type these two commands: TZ="/Pacific/Auckland" date date -u The former will show the current date/time in Auckland, the latter will show the current date/time in UTC. When I do that on my Linux box, I see a 13 hour offset, as expected. Also, if you look in the tzdata files (specifically, file "australasia") you'll find the rule for Auckland, which indeed says the base offset is 12 hours but DST is now in effect. It shows that the DST start date has changed a bit over the years, but the latest it has ever been is first sunday in November. So if your calendar program is showing today's time as 12 hours from UTC, that would suggest it doesn't do DST at all... paul On Nov 28, 2012, at 8:28 PM, Gemma Conn wrote: Hello, Can you point me in the direction of where I can double check that IANA has the correct time for New Zealand? I am worried that IANA has the wrong time for New Zealand, as Google Calendar which claims to use IANA Time Zone Database, displays the incorrect time for New Zealand. It displays GMT + 12 Auckland but it should be GMT + 13 Auckland, as we are observing Daylight Savings time. Sorry I could not find the right place to check this on your website - can you please check for me or tell me where I can check what time the IANA Time Zone Database has for New Zealand? I will let Google know if the mistake lies with them. Thanks Gemma Begin forwarded message: From: Paul Eggert <eggert@cs.ucla.edu<mailto:eggert@cs.ucla.edu>> Date: 29 November 2012 2:17:18 PM NZDT To: Gemma Conn <gemma@biozone.co.nz<mailto:gemma@biozone.co.nz>> Subject: Re: Fwd: [IANA #636310] how to check a time On 11/28/2012 12:49 PM, Gemma Conn wrote: I couldn't find the place on the IANA website where I can check a time... I'm afraid there isn't a simple way to do that automatically. I suggest you ask by sending email to tz@iana.org<mailto:tz@iana.org>. This mailing list is discussed in <http://www.iana.org/time-zones>.
From: Gemma Conn <gemma@biozone.co.nz> Date: Thu, 29 Nov 2012 14:28:26 +1300
Can you point me in the direction of where I can double check that IANA = has the correct time for New Zealand? I am worried that IANA has the = wrong time for New Zealand, as Google Calendar which claims to use IANA = Time Zone Database, displays the incorrect time for New Zealand. It = displays GMT + 12 Auckland but it should be GMT + 13 Auckland, as we are = observing Daylight Savings time.
I suspect the Google Calendar user interface may be contrary to your intuition. The selector for time zone only lists the standard time offset from GMT, without regard to DST status. A quick test suggests that the correct time is used for events. An event with start time in my local zone (US EST) and end time in NZ time has the correct duration. - Pat
Date: Thu, 29 Nov 2012 14:28:26 +1300 From: Gemma Conn <gemma@biozone.co.nz> Message-ID: <68A00F89-A38E-464A-8B6E-E4A5F7187A1B@biozone.co.nz> | Can you point me in the direction of where I can double check that IANA | has the correct time for New Zealand? IANA just provides a home for the timezone project to store & distribute the timezone database (& associated code), they don't (and don't pretend to) provide time mapping services. | I am worried that IANA has the wrong time for New Zealand, The database is correct, we believe - it shows summer time starting on the last Sunday in September, and continuing until the first Sunday in April. That seems to have been the rule for the past 5 years (from summer of 2007/8). | as Google Calendar which claims to use IANA Time Zone Database, | displays the incorrect time for New Zealand. Can't comment on that, but, using (relatively) current database (no changes to NZ data have been made any time recently) and I get (a few minutes ago now) date -u; TZ=Pacific/Auckland date Fri Nov 30 18:43:48 UTC 2012 Sat Dec 1 07:43:48 NZDT 2012 That's a 13 hour difference (as it should be). | Sorry I could not find the right place to check this on your website There is no direct place there to do that. You could download the database and code, and test it yourself, r you could just read the source from the database - but if you're not familiar with the format I don't really recommend that strategy. | I will let Google know if the mistake lies with them. Assuming it wasn't some kind of error of the investigation, that's probably what you need to do. kre
participants (7)
-
Derick Rethans -
Even Scharning -
Gemma Conn -
Guy Harris -
Patrick O'Donnell -
Paul_Koning＠Dell.com -
Robert Elz