You can create a timezone using only an offset via the static CreateCustomTimezone method on the TimeZoneInfoClass. the code for the factory I use is shown below.


public static class TimeZoneInfoFactory
{
public static TimeZoneInfo Create( double gmtOffset )
{
var name = String.Format( "GMT{0:+0.#;-0.#;#}", gmtOffset );
var offsetMinutes = Convert.ToInt32( gmtOffset * 60 );
var offset = new TimeSpan( 0, offsetMinutes, 0 );
return TimeZoneInfo.CreateCustomTimeZone( name, offset, name, name, null, null, true );
}
}


One question i have about your code is whether the offset alone is sufficient to determine a specific timezone (especially considering DST)? based on your code it seems that the name is not important, so that partially answers the question.