I encourage you to read one of my previous post on this thread, you find find much info about styling according to the weather.
Your dress will be fine (I had a big silk and tulle dress) and was fine in the hot days of July! A mermaid style (with the legs very tight) would be more difficult to wear in this kind of weather.
No worries for the mosquitoes...i did not have any when I was there, except one night at the beach LATE at night.
Also, like I said in my previous post, it is windy so I choose a long veil and I am really glad my hair were up, they stayed perfect all day. The wind and the humidity would not have worked well for my hair. Makeup was fine too, I brought touch up make up for the reception but did not even use it.