My confusion with Asia/Aqtau
autarch at urth.org
Fri Jul 18 05:34:07 UTC 2003
I'm trying to implement a parse/code generator based on the Olson DB
_text_ files (not binary).
I think I've got it mostly working, but there's some strange edge cases.
One of them involves Asia/Aqtau, and I'm trying to figure out if I'm
_really_ understanding what the file indicates.
The observances for this zone include the following:
5:00 RussiaAsia AQT%sT 1995 Sep lastSun # Aqtau Time
4:00 RussiaAsia AQT%sT
The RussiaAsia rules include the following rules which apply to those
Rule RussiaAsia 1993 max - Mar lastSun 2:00s 1:00 S
Rule RussiaAsia 1993 1995 - Sep lastSun 2:00s 0 -
Rule RussiaAsia 1996 max - Oct lastSun 2:00s 0 -
By my reading, this indicates the following transitions:
* On Sep 24, 1995 at 00:00:00 _local_ time, the offset from UTC changes
from 05:00 to 04:00. However, the DST rule is still in effect, so the
total offset goes from 06:00 to 05:00.
* On Sep 24, 1995 at 01:00:00 local time (2:00s == 1:00 wall when DST is
in effect), the rule changes so that DST is no longer in effect, and the
cumulative offset goes from 05:00 to 04:00.
Is this _really_ correct? It seems awfully strange to have an observance
change so close to a DST change. And if cases like these are possible,
it's really going to complicate my code. But if it is correct, I do want
to get it right in my code.
OTOH, if it's wrong, and such things don't happen, I'd be just as happy to
leave me code as is ;)
House Absolute Consulting
More information about the tz