The Carolinas are a great place summer or winter. This winter has been a bit colder and wetter than usual but most winters you get nice sailing days all through the cold months. In NC the average high in January is 52. You do get nights down in the 20's and a few in the teens. This year I am on the hard for a bottom paint and topside wax job, just waiting until it warms up a bit to get working :>)
I am in Beaufort, NC and if you are looking for a slip for the winter send me a personal message and I can connect you with someone that has slips available.
My nephew lives in Charleston SC, and it is a bit warmer, wonderful city, and wonderful harbor. Two marinas on the south side of the city but probably fairly pricey for transient storage. There is also a large marina up by the Yorktown on the North side of the harbor. What is your draft on the boat, another thing to consider?