A Time Zone is represented by a signed offset from Universal Coordinated Time (UTC). It is expressed in the format:

    <sign>hh:mm

For example, the UTC offset on the west coast of the United States is “-08:00” –local time on the west coast is 8 hours and 0 minutes ahead of UTC.

The .NET Framework 2.0 SP1 introduced System.DateTimeOffset value type. Sytem.DateTimeOffset supports Date, Time and UTC Offset components.

The TdTimeWithTimeZone and TdTimeStampWithTimeZone Provider Specific Types maintains information about the UTC offset.