Hi we are from Maine too (West Paris), we went last year in August. It was really hot but as long as we stayed hydrated and stopped to go inside when the kids needed to we were ok. The thunderstorms are a trip though, not at all what we are used to here at home, lots of lightning!!! People don't even seem to notice it is going on unless it is pouring down, I tend to steer the kids someplace inside until it is over, I don't want to be the one who plays lightning rod :smile:.
We have to travel during the summer due to the kids school schedule. I would say as long as you are prepared for the heat, take breaks when you need to and have plenty of water/powerade (we alternate between both each time we get drinks) you should be fine. Also given that here at home it is usually hot and humid by August it shouldn't be too much of a shock to the system.
I do agree about having plenty of changes of clothes, we went to AK and went on Kali river, my daughters got soaked, we left and had to stop at
Walmart, it was so cold in there from the air conditioning that they both caught cold. Just a tip, take a spare set of clothes w/you to the parks, leave them in the car or go back to the hotel before heading out. We won't make that mistake again, it made for a really uncomfortable drive home for them.
We just bought into DVC so we will be making yearly trips from now on

. Maybe we will see you there we will be at VWL from the 20th - 26th.