We went in December a couple years ago and will probably be going again in December. I love that time of year for the decorations and the cooler weather. It did get cold some evenings. We never have a chance to go back to the room in the middle of the day so we packed a backpack with layers. I packed two large wool scarves (the squarish kind) that I could put on under a light jacket, plus my rain jacket that would also keep out the wind. And of course, a hat that covers your ears really help, too. Having these small layers was easier for us to carry around than a big coat.