Its definitely hot, its definitely packed, but I would still do it again! My parents always planned family vacations at the end of August so my first 4 WDW experience were at that time. Last year, my husband and I went in the beginning of June and it was still hot, but it seemed slightly less packed. We're planning our next trip for next year and we're hoping to go in September or October. If you do go in August, I'd try to get fastpasses to the more popular rides right away. Its not fun standing in line for 2 hours in super hot weather if you can help it! Either way, I hope you have fun whenever you do go!