I've cruised in Sept, Nov, Jan & Feb and the weather was great for all of them. Those are the months we have found the best rates. I live in FL, & it does get chilly here at times. (When it's in the 80's during the day and in the 30's at night it's a pretty big shock to your system!) Even when it's chilly in the port, it's still beautiful in the Caribbean! And I have to say I agree with the poster who said any time is a good (GREAT) time to be on a cruise ship!
Sovereign of the Seas, Royal Caribbean 11-17-03
Fascination, CCL 2-14-05
Fantasy, CCL 2-05-06
Elation, CCL 9-24-06
Carnival Victory, CCL 1-28-07
Sovereign of the Seas, Royal Caribbean, 9-24-07