Whilst not mainland Europe, we took a break in December to Gran Canaria. This was a first, I had never visited the Canary Islands before, pretty much because I thought they wouldn't appeal. During our stay the weather was fantastic, sunny mid to late 70s. I was pleasantly surprised, I believe the temperature doesn't fall below 70 degrees in the coldest months of January and February. I would certainly go back for winter sun, we loved where we were staying in the south of the island, Maspalomas, we didn't visit the capital, Las Palmas, which I understand is the 8th or 9th largest city of Spain and it's islands and not devoid of culture, I believe Christopher Columbus stopped off there on his way to the Americas. Gran Canaria has a green and mountainous interior with lots of pretty villages.