Add Jamestown (Saint Helena, Ascension and Tristan da Cunha) to your list and use my-locations table to visually convert it's time to another timezone or city time.
Mouse over the colored hour-tiles and glance at the hours selected by the column.

Current time zone for Jamestown (Saint Helena, Ascension and Tristan da Cunha) is GMT, whose offset is GMT+0 from Greenwich Mean Time (GMT).

The IANA timezone identifier for Jamestown, Saint Helena, Ascension and Tristan da Cunha is "Atlantic/St_Helena"

It currently does not observe Daylight Savings Time.