I never went the week after Thanksgiving, but I know many people who have and swear that it's the best time to go, crowds and weather wise. I've been to WDW in August, and "hot" just doesn't describe it! It's very sticky and humid, I will start to sweat from just standing in one spot for a few minutes! Of course it's still WDW, but if I had to choose I would go during a cooler month.