We were in Disney last August and while the temp there was HOT when we arrived - it was HOT in NJ too. Three days into the trip it was scorching mid 90's in NY and it was 70 in Orlando - lasted 3 days, we couldnt even enjoy the pool at night - we were FREEZING - had to soak our tushies in the Hot Tub! My boy who loves cold water even gave up and jumped into the spa to warm up.
I have 4 weather thingys set up on my MSN home page - North Jersey, South Jersey, Orlando and St. Pete.... interesting during the summer months that there really isn't a big gap. Sometimes they are cooler. Also there is only a 1 degree average temp change between August and Sept in Orlando.
It is only the Hurricanes you need to worry about... free dining only means they charge you 100k for the life vest and boats
Enjoy!