This won't surprise many people, especially those who have known me for a while.
Winter. Yes, winter. Pure and simple. Why? I love the cold weather, I love the crispness of winter, I love looking at the frost and snow and seeing nature in a white world. I love the long dark nights, the fact I can put the lights on and pull the curtains at around 3:30 p.m. and not wake up to bright sunshine.
I'm not a summer person and never have been. I don't like the heat (it makes everything worse for me) and too much constant sun (as we are currently experiencing) gets me down. Also, I work on the basis you can always keep warm, but there's a limit to how much you can take off to keep cool. I hate being over warm.
I suffer from SAD in reverse of most people.
So constant winter would make me a very happy bunny.