I found the best shorts for Florida weather:
http://www.columbia.com/Women’s-Sandy-River™-Short/AL4573,default,pd.html
These can be found at retailers like REI. They''re an above-the-knee length. They're made of a moisture-wicking, cool material and are so comfortable! They're quick-drying, too, and would be great for rides where you might get wet (like Splash). They are even easy to hand-wash in the sink at night, if needed, and will be dry by morning.
One thing to think about is that you'll probably get very sweaty during the summer, and will go through more clothes than you might think. At home here in Washington, I might wear a pair of shorts or t-shirt a couple of days before washing. In Florida during the summer, I feel the need to change clothes in the afternoon sometimes - I got that sweaty! With these shorts, you can hand-wash them at night so you'll need fewer pairs. I brought three pairs for a seven-day trip(and had even brought other types of shorts to wear) but ended up sticking with the three pairs of these hiking shorts all week. You'll love them!