June is one and done for me. It's just too hot and humid for my taste. I stay away from the whole state in the summer. When I did June, I just did two theme parks and did water based activities all the other days (just way more pleasant to be in the water). It's a great time for the beach and waterparks. I personally don't like doing theme parks in that kind of weather. But perhaps I'm a hot weather weeny. There are plenty of other people who go and who are repeat visitors.
For me:
Pro: Even the ocean for a day trip (e.g. Clearwater beach) feels warm enough and the pool and waterparks are heavenly.
Con: I usually go to Orlando for the theme parks and I don't care to tour in theme parks with the typical heat and humidity that time of year. The crowds for theme parks are moderate, but if you don't even want to be there and just want to go in for AC or into the water that's not much of a saving grace for me. Sure you can bring a spray mist fan, take breaks, drink lots of water, use special towels to cool off, but even with all that I still don't like going to the theme parks in that weather.