Translate Windows timezone to TZID?

Mark Davis mark.davis at
Tue Jun 14 21:42:53 UTC 2005

We have *a* mapping of Windows IDs in CLDR. See

While we have tried to make it accurate, it is difficult to get a good match
because the Windows IDs encompass what would be many different TZIDs.


----- Original Message ----- 
From: "Dave Cantor" <dcantor at>
To: <tz at>
Sent: Tuesday, June 14, 2005 13:01
Subject: Translate Windows timezone to TZID?

> 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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