Barometer / Thermometer / Tide clock

My missus was thinking about getting a barometer / thermometer for me.

She did some research and found electric ones which also have a tide clock.  Has anyone got advice about these tide clocks.  Are they accurate?  How can it tell where you are in relation to the tides.

We all know the barometric pressure affects the fish, so I'm looking forward to studying this a bit more.