Like others have said, I've been a number of times in Dec. and have had just about everything weather wise. I will say, since I'm from Georgia, it's never been shorts weather for me. I have been able to wear just some lighter leggings and a long sleeve shirt but never shorts. But, again, I'm from Georgia and if it gets below 75, most of us are wearing at least long pants and long sleeves. I was there last year the first week in Dec. and most days started out with a jacket (hoody type) and during the day was able to get away with a long sleeve shirt. At night, I had on a hat, heavier coat and gloves. It rained about 2 out of 4 days as well. I was there that same week the year before and while no rain, I did still have to wear a scarf, heavier jacket and hat at night and a lighter hoody during the day. It didn't rain that year. I've been the week before Christmas and was cold all the time but it was sunny. Crowds were, well crowds. It depends on what you think are heavier crowds and what your tolerance is for them. I don't remember any bottle neck places except the usual around PP at MK but waits were not walk ons either.