I have a pair of sunglasses with very vented lenses -- the model is Tifosi Slip -- and I wear them in cold weather (below 40). When it hits 15, the Slips fog up at stoplights too. Then I switch to big dorky alpine ski goggles ... (I actually have a WSD pair by UVEX that isn't uber-huge for ski goggles, but they still look a tad dorky on the bike I"m sure).