I live in Florida myself, and my car has almost 140,000 miles and I use regular Valvoline 10w-30 oil. I beat the crap out of it on the weekends at the autocross, and the oil stays clean up to every 4,000 mile oil change. So as long as you're not burning any oil, I'd stay with what has worked for you.
I have a 89 Ford E-150 van I bought new here in FL, I run straight 30w in and it has well over 200,000 miles on it with no problems. I'm a firm believer that weight doesn't make much difference in the FL weather except that a higher weight will decrease you fuel milage. Now if you lived up North that would be a differnt story.