'How to translate between Windows and IANA time zones?

As described in the timezone tag wiki, there are two different styles of time zones.

  • Those provided by Microsoft for use with Windows and the .Net TimeZoneInfo class (when running on Windows) are identified by a value such as "Eastern Standard Time".

  • Those provided by IANA in the TZDB, and used by the .NET TimeZoneInfo class when running on Linux or OSX, are identified by a value such as "America/New_York".

Many Internet-based APIs use the IANA time zones, but for numerous reasons one might need to convert this to a Windows time zone id, or vice-versa.

How can this be accomplished in .Net?

c++sharp.nettimezonenodatime


Solution 1:[1]

Starting with .NET 6, it is finally possible to work with time zones in a cross-platform manner, so these manual workarounds are no longer needed.

The TimeZoneInfo.FindSystemTimeZoneById(string) method automatically accepts either Windows or IANA time zones on either platform and converts them if needed.

// Both of these will now work on any supported OS where ICU and time zone data are available.
TimeZoneInfo tzi1 = TimeZoneInfo.FindSystemTimeZoneById("AUS Eastern Standard Time");
TimeZoneInfo tzi2 = TimeZoneInfo.FindSystemTimeZoneById("Australia/Sydney");

Note that, as specified on the link, the .NET Core Alpine Linux-based Docker images do not have the necessary tzdata installed by default, so it must be installed in your Dockerfile for this to work correctly.

Solution 2:[2]

I know this is an old question, but I had a use case I though I would share here, since this is the most relevant post I found when searching. I was developing a .NET Core app using a docker linux container, but for deployment on a windows server. So I only needed my docker linux container to support the windows timezone names. I got this working without changing my application code by doing the following:

cp /usr/share/zoneinfo/America/Chicago "/usr/share/zoneinfo/Central Standard Time"
cp /usr/share/zoneinfo/America/New_York "/usr/share/zoneinfo/Eastern Standard Time"
cp /usr/share/zoneinfo/America/Denver "/usr/share/zoneinfo/Mountain Standard Time"
cp /usr/share/zoneinfo/America/Los_Angeles "/usr/share/zoneinfo/Pacific Standard Time"

Then, in my .NET code, the following worked without any modification: TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time")

Sources

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Source: Stack Overflow

Solution Source
Solution 1
Solution 2 EverPresent

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