I am writing an application that has to know a few time zones, and I can't figure it out in .NET. The two locations that I am using are Dallas and Frankfurt. I need to know, at anytime of year, what the time is in both locations based on GMT (UTC). Anybody got any good ideas? I can get GMT(UTC) time and I can do the conversion manually if I have to, but how would I say "if between march and october then offset from GMT would be -5, else offset would be -6" ?