The music I listen to is very much affected by the seasons. In the winter I tend to listen a lot to calmer music with vocalists of warm, close, comfortable voices (Leonard Cohen, Devendra Banhart, Laura Marling, Johnny Flynn, modern Dylan just to name a few).

I tend to go for more easy-going, rhythmical, refreshing stuff in the summer. Listening to Björk is, to me, the musical equivalent of having my face dabbed with ice cold water, it's very effective on hot days. Post-rock stuff like Explosions in the Sky is great in the summer also, The Shins works very well, some reggae and electronica/synthpop is unavoidable, and, what else... some classical pieces like Pärt's Fratres work wonders.