This last winter we had the Mediterranean's best weather over the Christmas period here in Cyprus; we had all our doors & windows open all day Christmas day & had lunch with neighbours outside on Boxing Day. Then we had a frost of -4 on New Year's Eve..........
If you want hot, as opposed to warm, you'll need to look further afield than the Med or The Canaries; winter 2008 was one of the mildest for years in Cyprus, and daily temperatures were in the 19 - 23 range - warm enough to go out in a T-shirt without a coat, at least in the middle of the day, and I saw a fair number of British holiday-makers in shorts & vests - though of course it would have felt much warmer to them having come from such a chilly winter in the UK. The Canaries were consistently a couple of degrees cooler.