Now I don't mean this in the literal sense, Leontes doesn't have himself in a room with a snow-maker on 24/7 while catching hypothermia and drinking hot cocoa. Nope, I think that he is in "winter" in his soul. His mind is frozen in the moment 16 years ago, his heart gone cold and hope shoveled from his soul. He is in "winter" because he believes there is no way he can ever come back from his crimes. (Especially since Paulina keeps blasting him with icy stares and bitter guilt trips.)
But in Act V scene 1, I believe he begins to see the sun's rays in the distance. He slowly begins to thaw out when his long lost daughter appears and finally bursts through the ice when Hermione is revealed to be alive! His winter had ended and he has found hope, and springtime, once again.(Just a side note, I think that if I were in charge of costuming for this play, I would keep Leontes in dull colors until the final scene. I would then choose to put him in a more earthy or spring-time color to show that vibrant hope that is returning to his soul and the new happy reality he has found.)
