I've been walking 20-30 minutes 4-6 times per week, even throughout the winter. As long as the snow wasn't deep, I was able to get out and walk, even if it meant carefully walking in the street. On the snowy days, I was able to shovel for exercise. This has made a great difference in my moods this winter. Bundle up and walk...it's amazing how it clears the mind and soothes the soul.