Translate Windows timezone to TZID?

Dave Cantor dcantor at
Tue Jun 14 20:01:29 UTC 2005

I've been thinking about this problem for a while.  Anyone have 
any thoughts?

Suppose you have a portable computer running Microsoft Windows 
(whatever version you dislike least) which you take with you when 
you travel.  When you power it up and you're in a timezone 
different from the one you last used it in, you use Windows'
Adjust Date/Time dialogue to set the correct timezone.

Now Windows has bogus names for the zones, like
"Dlt"="GMT Daylight Time"
"Std"="GMT Standard Time"
"Dlt"="Hawaiian Daylight Time"
"Std"="Hawaiian Standard Time"
which you can read out of the registry.

Suppose I want to get the correct name of the time zone
(from which maybe I'll generate the correct abbreviation).
So for GMT, the proper strings would be 
"Greenwich Mean Time" for standard time, and there is no daylight 
time.  For Hawaii, I believe that's properly Hawaiian-Aleutian 
Standard Time; again no daylight observance.

Is there a way anyone can think of to map the incorrect
Windows text strings to correct text strings algorithmically?

(Too bad Windows doesn't have the exemplar city name in its 
database of time zones.)

Dave Cantor

David A. Cantor
Groton, CT  06340-3731      DCantor at

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