We were there last Nov the week of thanksgiving. It was about 75 during the day (we wore shorts and short sleeves) but it got colder at nite, where you definetly needed a jacket or sweatshirt. The Wed b4 thanksgiving it was so windy once the sun went down we actually left the park b4 we forgot jackets and my kids were freezing.
The weather is nice to do the parks, not sweating in lines is a plus, plus the crowds (with the exception of Thanksgiving) are not too bad. I think its a great time to go......................Oct. is even nicer for the no crowds!!!!!!!
You will have fun no matter when you go
HTH