We booked in advance our own excursion. They had a provision of bad weather cancellation or if our ship didn't show up. I didn't get super details, but most companies probably have a similar policy. The large companies did have persons available in the port area, and then right outside the secure area were people proimarily getting taxis and busses to places as part of a tour.
It was raining when we arrived, but by the time we got to the yacht club, it had stopped. Our Captain pretty much kept an eye out for weather and it didn't impact our day. The swells outs past the reef wall (which we requested) were too much for my 1 year old who got sick, but the rest of us were fine.