The south coast of Portugal and the east coast of Spain have the mildest winters in mainland Europe, but it can still get a bit nippy (15c/60F highs in the day) during the coldest parts of the year. If you want to travel a bit further the Canary Islands will be warmer.
Compared to northern Europe where this year has seen 5 months of winter, that's like paradise though :-)
I'm on the opposite when it comes to this: I like to have 4 proper seasons and all that comes with it. I remember visiting Malta and even though the sea and nice weather is nice,I don't think the novelty would last for too long, especially when you have to go around sweating all the time because it's simply too hot.
Compared to northern Europe where this year has seen 5 months of winter, that's like paradise though :-)