Caribbean/mexican Cruise in May

just curious because I've seen conflicting results on Google.

first my question is how hot and humid is the weather? I've never been on one but my mom says that Jan or Feb sometimes is too cold on the cruise and perfect on land but may is great on the cruise and land is fine. however when I Google like Belize it says 85-90 and super humid, so how is cruising Western Caribbean in May actually?

secondly how do like Riviera cruises compare to Western Caribbean? can you still see ruins anywhere? how is the experience different between the two?

thank you!