I did my
FL. Circumnavigation trip a few years ago in the Spring, so we were still having cold fronts blow thru about once a week, and I was real concerned about the offshore stretch from Sanibel to Cape Sable, as there aren't many places to find shelter from west winds along there! Delayed the trip till mid-April and had almost perfect weather, but the bugs kept us out of the Shark river/Whitewater Bay area in the Everglades that I wanted to check out. I think exploring that area would have to be a strictly wintertime trip!
August should be good for your trip, provided there aren't any tropical systems brewing in the Gulf!