Add ADT (Atlantic Daylight Time) 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 ADT (Atlantic Daylight Time) is ADT, whose offset is GMT-3 from Greenwich Mean Time (GMT).

The IANA timezone identifier for ADT, Atlantic Daylight Time is "ADT"