TZ database content

Alex LIVINGSTON alex at
Tue Feb 13 02:23:40 UTC 2001

At 02:24 -0800 2001-02-12, John A. Halloran wrote:
>You mention Lord Howe Island and then ask where South Australian Time with
>a standard of -10:30 comes from.  Lord Howe is the only Australian location
>that observes South Australian Time.  The daylight saving offset appears to
>have changed however from one hour to half an hour in 1985.  There is an
>Australian time zone for this offset, but the abbreviation would not
>correlate to the correct standard time zone.

There is a state of Australia called South Australia. It lies 
entirely in the current Central time zone of the country. It never, 
ever observed -11:30 as an offset, and it never observed -10:30 as a 
"standard" offset. Lord Howe Island lies in the Pacific east of 
Australia's Eastern time zone and two time zones away from South 
Australia, having about as close a geographical relationship to South 
Australia as Bermuda does to Texas. How intelligible (to humans) is 
"South Australian Time", then, as an offset tag for the time on Lord 
Howe Island? How are people supposed to know that it does _not_ 
relate to South Australia?

>Myanmar/Burma and the Cocos Islands, both standardized at -6:30, are in the
>list as North Sumatra Time.

Not used in north Sumatra for decades. How meaningful is that?

>Norfolk Island at -11:30 is standardized to what the list calls New Zealand

You mean "New Zealand Time (pre 1940)". I think you'll find that in 
fact it's pre 1947. And who would relate that offset tag to Norfolk 

>The Marquesas Islands in French Polynesia at -9:30 are standardized to what
>the list calls Australian Central Standard Time.

The Marquesas Islands are on what you call +09:30 (UT-09:30), not 
-09:30. They lie in the eastern Pacific, nowhere near central 

>The list certainly does not have the -12:20 standard of Tonga before 1968,
>but it does have its -13:00 standard since then.  The list calls that
>Chukot Time.

Another generally unhelpful name.

>Fiji standardized at -12:00 uses the zone that the list calls New Zealand
>Standard Time.

And another.

>Afghanistan is standardized at -4:30, which is in the list as Iran Daylight
>Time.  Afghanistan could have its own zone.
>Nepal at -5:45 since 1986 is not in the list.
>I was not aware of the Chatham Islands east of New Zealand and east of the
>International Date Line at -12:45 and -13:45 in summer.

But the Chatham Islands, though east of 180 degrees longitude (and 
thus in the western hemisphere), are _west_ of the date line, which 
necessarily diverges from the 180-degree meridian to lie east of the 
Chatham Islands.

Closer (presumably) to home, you've also left out Newfoundland 
Daylight Time (+02:30).

Please pardon my indignant tone :-) .


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