In winter there are not all that many tourists, so it's easy to find a place at short notice, and often cheaper as well.
We came on a two week climbing trip. Temperatures are still fine for climbing (or for hiking or cycling for that matter), and on 26 December it was warm enough to take off my shirt. Mind you, I was the only one doing that, and I drew a few surprised looks from some other tourists. But hey, I'm warm-blooded!