My dad has practiced a semiannual ritual ever since i can remember: At the autumnal equinox, he starts growing a beard for the winter months. On his birthday, April 13 (or sometimes on the vernal equinox if he's feeling lazy) he shaves it off for the summer. Cool in summer, warm in winter--makes perfect sense to me, although the first time I see him after he shaves is usually a bit of a shock, and makes me think of Mr. Pickwick...