According to my atlas, there's a small band which runs around the Cork and Kerry coasts of Ireland, and the coasts of Cornwall and part of Devon in England where the average January temperature is 45 deg. (In the case of western Cornwall, the areas meet to cover the whole far-west of the county.)
The is certainly the mildest winter climate temperature-wise in the islands, though unfortunately it's not the driest! I certainly remember my years living in Cornwall as having very mild winters. It did snow one year though!
