Seriously...really really really hot
like ppl wanng go to their air conditioned rooms hot,

As MousekaMaddi says, end of Sept is HOT, early Oct is nicer... crowds are relatively light. Early Dec the weather is nice, but maybe even a little chilly some days depending on where YOU are from and what YOU are used to. We are from Montana, and I don't care how cold the locals say it is, we always find it to be plently warm in FL. Of course, we wear short-sleeves and shorts at 55° in MT, we are weird that way...![]()
Anyhow, I think the biggest question if *I* were considering those two times would be; What do you most want to see/do? Would you most enjoy the fall decorations and the Halloween events? Or would you most enjoy the Christmas decorations and events? Would you like to do the Not So Scary Halloween Party? Or the Very Merry Christmas Party? Would you like to see Candlelight Processional? There is so much to do at either of those times... either one would be an awesome time to visit!![]()
Go early December, especially if you've already experienced MNSSHP and the Halloween decorations. The Christmas decorations are supposed to be magnificent (I've never gone during Christmas season) and the weather is great. With the heated pools, it's even swimmable if you're brave!

Brrr
but if it's the first week, you're USUALLY going to have it fairly good. If you're really "into" swimming and water parks, I'd be sure to go early October.
We were there for the 1st week of Dec. in 2006, and sometimes there were only 10-15 people in the lines. We walked through, and I mean THROUGH ... to the beginning ... on all the biggest attractions (Mission Space, TOT, and all the others except Soarin') sometimes 3 x in a row!
It was crazy. Would you go either the end of Sept/early Oct OR the beginning of December?
We're trying to decide on next year's trip and are looking for some advice! TIA!
Shelby