Well, being from Florida, I'm pretty use to strong sun and high temps with high humidity. The temperatures while onboard the ship never really bothered me. Although, if you're out in the sun watching an event or something (I'm thinking ice carving demonstration) it can get warm.
Unlike the other posters on this thread, I
didn't find Key West to be worse than Grand Cayman and/or Cozumel. Again, this could be because we were doing different things and in different areas or just that we're use to different types of weather.
In Grand Cayman we went to Stingray City with Captain Marvin. So, being in the water was wonderful. Afterwards we walked around dock area and did some shopping. It was hot, with little breeze from what I remember, but wearing a light (white, cotton) t-shirt and just swim shorts helped a lot. Many of the stores are also air conditioned so we weren't out in the heat for a long period of time.
Cozumel was a LOT different. Tulum was hot. And, in reality, I don't think I would do this excursion again during that time of year. It really made it somewhat unenjoyable. Don't get me wrong, the ruins are magnificent in and of themselves, but they might better be visited at a cooler time of the year. The on saving grace of this excursion was the fact that the ruins are right on the beach. A very beautiful one to be sure. After the guided tour we ended up snapping a few pics and then heading down to the beach where we just enjoyed the water until it was time to catch the tram.
Regardless of which port you're in the one thing I can advise is to watch the amount of sun that you're getting. As I said, being from Florida I'm use to strong, direct sun. But even the Florida sun doesn't compare to the Caribbean sun. The closer you get to the equator the stronger the sun. And I think this is especially true during the summer months due to the tilt of the Earth.
Anyway, I hope you enjoy your cruise! The weather will be warm but that's why we go to the Caribbean in the first place!
