I went around this time last year (the week before Thanksgiving). Early in the week, the crowds were very manageable. Some rides at MK had long lines during the busy times of day, but all the other parks had very little wait for anything. Great time to go.
Weather is unpredictable. In the 8 days we were there, we only had 1 brief shower. The weather for a couple days was in the high 80s, but most days it was in the mid 70s. It would get chilly in the evening and early morning (low 50s and 60s). For us, a wind breaker or fleece jacket usually fit the bill.
So it could be hot or cool. Bring clothes that you can layer easily.