Its been very cold here in NC too. Tough winter so far. No snow though. I did manage to put in 40 miles this past Saturday, and 40 on Sunday too. I was very happy since it gave me confidence in my ability to ride in cold weather. About 23 degrees when we started, 33 when we finished. But we ride slow and that's fine. Anything is better than the trainer.
Having said that, I think the 23 degree point is just about my limit. Below that and I'm at the "Y" in the swimming pool.