How any temperature feels will depend on the humidity. On average it is not as humid as FL here, but it has been more humid than usual the past few summers. And it was unusually humid this past week with warm rain because the normal low pressure system that brings rain from the north has been pushing the rain up from Mexico. It's been in the high 70s and scattered showers. Very few times have I been standing in DLR on an 80+ degree day with 40% humidity and thought, "I'm not as uncomfortable as I was in Orlando or New Orleans." It's still not fun when that happens.
As far as crowds, Food & Wine seems to be drawing crowds. DLR is pretty much always crowded for at least part of most days. You're definitely not going to go for 2-3 days and not encounter crowds anymore.