For the past five years we have lived aboard and cruised on our 27 foot sailboat, cruising the coasts of Florida in the summer and staying in the Keys during the winter. No air conditioning! Love it! BUT, we anchor out and don't stay in marinas! Would need A/C if we stayed in marinas. We are only too hot when on the land! Fans, especially over the bed are essential.
I lived in Connecticut for 22 LONG years. Grew up on Arizona, lived in the south some, visited Singapore and other tropical areas, lived in Florida the past 11 years and I am here to tell you that Connecticut was the most humid place and on a hot day the HOTTEST and most uncomfortable place I ever lived!! All my New England friends were always saying they could never live in Florida as it is too humid and hot! I just smile at their uninformed opinions. :-)