The fact is Weather cannot be accurately predicted more than 3 days out. The best weather site is the local one www.wesh.com It is a regular 5 day forcast, but since it is Orlando based it is the most accurate AND they have a webcam in Universal Since we are in Orlando often I have this on my favorites so I can always check the weather!
If you go to www.weatherunderground.com and go to "orlando" you will find a link called "trip planner" if you click on that and enter your dates it will give you the weather history from years back. That will give you an idea of what to expect as far as temps...