I was also there last year when it was sooooo cold. Being from Texas I wore jeans, a tshirt, a fleece over that, then a coat, gloves, hat, and scarf and still almost froze. I was also there a few years before and almost froze. I usually go every year either the first or second week of Dec (going part of the first week this year) and the weather is all over the map. Some trips we'll start off in capris and tshirts, then by mid week be in coats and jeans, then by the end of the week would be swimming and wearing shorts. You just never can tell with Florida weather. I usually keep an eye on acuweather.com and don't pack until just a few days before we leave. Even then, accuweather.com is frequently wrong, so I pack the majority of my suitcase according to what accuweather says the weather is going to do, but still pack a variety of winter and summer stuff anyway. Even if accuweather says it's going to be warm, still include at least one pair of jeans/sweats, sweatshirt, fleece, and a coat. Also throw in a pair of thin gloves, a scarf, and a warm hat. They don't take up that much room and you never know if you'll need them. On the other hand even if the forcast calls for cold weather throw in a a few pairs of shorts and a swimsuit. I know one year the forcast was for cold weather so that's all we packed for and we were looking for some shorts by the second day. Dec is a beautiful time to go, but you need to pack for all eventualities. The weather is very unpredictable.