We went Jan of 05, I am born and raised New Hampshire, if you put things into proper perspective it was warm, if you lived ina warm climate it was cold a couple of the days, I mean jeans, tee shirt hooded sweat shirt and LL Beans fleece vest (which by the way is how I dress for winter here at home most times) for touring all day one day in Epcot, another day was tee shirts and shorts and into the pool in the afternoon.
If you are traveling from a cold climate bring your cold weather gear just in case. The thing we found that helped was the little stretchy gloves that wal mart sells for a buck, lite cotton but warm enough if it is cold and winding to keep your hands from getting to cold.
Hope this helps Dave
PS low crowds sometimes did not even get off rides they waved us threw for a second round