Think about southern humidity before you consider August. I am from Oklahoma where we set a record for days in the triple digits this summer. I can be comfortable in Oklahoma heat, but I hate Florida summers. I am completely unwilling to do a Disney World trip June-Sept. It's not just hot, it's miserable. You start sweating the minute you step outside and you stay sweaty the entire day. People in general seem more grumpy when they are uncomfortable and it seems like everyone is on edge. For me at least it really impacted the enjoyment I got out of the trip.