You're going to have more crowds in June because you have a greater amount of school kids off in June than in the middle of August. However, you will have the free dining crowds in the middle of August. The FD bounceback begins August 15th and the
predicted general public FD might also start 8-15.
We go in August every year and even though it's very hot and rainy, it's less crowded than June and July. Many schools have started back in the South and West in late July and early August.
As long as you've made your ADRs, I would go in August, even if you're there during FD. Just absolutely make sure you have ADRs for your table service meals
Here is a great site with crowd calendars to help you plan:
http://**************.net/planning-...in-order/estimating-walt-disney-world-crowds/