I cruised to the Bahamas July 29th 2007 with my son and it was the more horrid heat & humidity I'd ever experienced. Arriving back aat Port Canaveral, the news that night reported it was 101 degrees but compared to how it felt in the Caribbean, it 101 only felt like 80 degrees to us! We couldn't believe it was really that hot out. I'll never complain about a Chicago summer again.
It was so humid out we couldn't enjoy the excursions to the fullest. I especially remember just getting off the ship and waiting for the excursion gropu to get together, even under a shelter, we were already sweating buckets just standing still.
I will also never cruise to a tropical climate in the summer again. That's what spring-winter-fall are for! Summer is for perhaps cruising to New England or Alaska or anywhere else north of the southernmost US states.