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    Re: time zones question...
    From: Geoff Kuenning
    Date: 2000 Feb 28, 12:54 AM

    > Here in S.A., we are 2 hours ahead of UTC.
    But only in the summer, right?  Do you observe daylight-savings time
    in SA?
    > A student of mine who did a celestial nav. course with me pointed out in our
    > local telephone directory that New Zealand time is given as being 11 hours
    > ahead of S.A. time. This would suggest that N.Z. is 13 hours ahead of UTC.
    > According to the directory, winter times are given. (Is N.Z. really 13 hours
    > of UTC as suggested?)  This seems a bit strange. Here in S.A. we keep
    > standard time (SAST), but N.Z. doesn't appear to span more than one time
    > zone so would they not just keep a zone time?
    A quick check of the Unix timezone databases indicates that New
    Zealand is indeed 13 hours ahead of UTC:
            % env TZ=NZ date; date -u
            Mon Feb 28 20:48:17 NZDT 2000
            Mon Feb 28 07:48:17 UTC 2000
    (The "env TZ=NZ date;" part says "tell me the current time in New
    Zealand, while "date -u" says "tell me UTC right now".)
    I don't know the reason, but my best guess is that it is historical.
    In the winter, NZ would be 12 hours off of UTC, and thus could
    reasonably choose to be either ahead or behind.  I suspect that the
    decision was made before daylight time was invented, or at least
    before it was commonplace.  They chose 12 hours ahead, and thus in the
    summer they are 13 ahead rather than 11 behind.
    (It boggles the mind to think of the confusion that would be
    introduced if they went from 12 ahead to 11 behind each October, and
    the reverse each April!)
        Geoff Kuenning   geoff@cs.hmc.edu   http://www.cs.hmc.edu/~geoff/
    Orchestra retrospectively extremely satisfied with symphony [No. 1] as
    result of barrel of free beer.
                    -- Gustav Mahler, post-premiere letter to Arnold Berliner

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