I like seeing the clock but the most useful thing when you are out and about from a marina is the barometer. I know there are lots of forecasts and NOAA and
internet and PredictWind - I use them all - but you can always
forecast the weather yourself because you are there in the spot on earth. Big forecasters and models cover huge areas, huge, and so things are an average wind and wave speed but our boat is in a particular spot on earth. the weather where we are at any time may not be the average weather!
precise barometric pressure is not important as watching the rate of change in pressure.
with your eyes on the sky and wind direction, noticing cloud type, season, and barometric changes you will have the information you need to keep your boat and passengers comfortable and feeling safe. A barometer is a fantastic tool.