Add Mar del Plata (Argentina) 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 Mar del Plata (Argentina) is America/Argentina/Buenos_Aires, whose offset is GMT-3 from Greenwich Mean Time (GMT).

The IANA timezone identifier for Mar del Plata, Argentina is "America/Argentina/Buenos_Aires"

It currently does not observe Daylight Savings Time.