Robert Elz kre at munnari.OZ.AU
Tue Feb 22 13:00:12 UTC 2011

    Date:        Tue, 22 Feb 2011 11:14:18 +0000
    From:        jrl <jrl at>
    Message-ID:  <E468A544C5BEF74DBF22CAAB3FD50DE810F47BBB at UNIVERZ.terraatlas.local>
  | What is the correct rule for Macau from 1980 through 1999?
  | Did they return to LMT?  

I wonder if there is any way we can make the documentation clearer
that the rules do not specify intervals, but transition points.

People keep asking questions (like this one) that make no sense at all
if the rules are interpreted correctly, but would be perfectly legitimate
if the rules were doing something like "specifying the period when summer
time applies".

Since this mistake is so commonly made, it must be a problem with the tz
documentation.   Unfortunately, I can't see it (which is often true when
someone who knows the answer tries to see why others cannot see it).

Does anyone have any ideas how we can make this clearer?   Is the problem
that people are just reading the data files, and ignoring the documentation?
Do we need to add some explanatory comments in every data file?


ps: the Macau rules say that the last time there was a std/summer time
transition in Macau was the 3rd SUn in October, 1980, since then the
only change has been the change of time zone abbreviation when Macau
became part of China again.   So, no, it dod not revert to LMT, there simply
were no more transitions - and once you understand that the rules are
used to specify transition points, this is really all very obvious.

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