I go through some amount of emotional up-and-downs in the winter, but not really laziness.

I always feel lazy, but when it's cold and snowy I have an actual excuse to stay home in bed.

Nope, most likely due to my condition, I am very active during winter and practically comatose during summer.

Seasons don't affect my laziness, I'm lazy year-round but probably more so in the summer because it's hot and I despise being hot. So I move as little as possible.