My DS and I were just talking about this last night as our trip is coming up soon! When we go to dinner, we always bring a sweater or sweatshirt. The A/C gets too cold for us. If we are in the parks during the day, we usually just get counter service so don't have to worry about being too cold, but if you are going for a long sit-down dinner (ours are usually 2-3 hrs) and think you might get cold, definitely bring a sweater.