Yeap, as nluvwithmickey said, anything's possible...I'm going to say to be prepared for anything.
It could be 80 or it could be 60. Just depends on those cold fronts, but you'll probably have to bring clothes for "all seasons". Just keep your eye on the weather the week before you go.
We've had early Decembers where we only needed a light jacket the whole trip for night time, another where it started out humid and warm with rain, turned cold and kept raining but then warmed up to the 70s. Last December some nights were just downright cold! And some were pretty comfortable.