The best website that I know of (and I learned this from Christi) is to watch windguru (
Windguru - Cozumel, Mexico ) and to use a little common sense. Any thing further than 2 - 3 days out is questionable data. A wind direction past North in a westerly direction down to due South with a speed over 10 Knots and you have reason to be concerned. If you are in the downtown area and observe sea water spraying over the seawall, go back to bed. Even if the port stays open in questionable conditions your dive op may elect to stay in port, with good reason. Last Fat Tuesday the harbor opened late in questionable conditions, I think everyone's bitching at the port captain for previous decisions influenced this. The 3P boat led the charge out of the harbor, we attempted a pickup at Fiesta Americana and the owner was on board and reassessed the situation and decided it was not safe and returned to port. I and everyone else on board agreed with the decision. Most ops stayed in the harbor and I talked to one DM who went out and he wished they has stayed in.
As Christy stated often the decision is made late and if the port was closed the previous day the announcement to reopen may not come until after 8AM, even though the sea conditions have obviously settled down. If the op you are using is also planning to use the same boat for an afternoon trip, it is not going to wait around long in the port.
. Based on the current windguru page I would be very surprised if the port does not reopen. 
