Summer and winter, on long rides I wear thin merino toe socks and a thick wool outer sock in shoes that drain well. Comfortable feet in most all conditions. In steady rain my feet themselves stays pretty dry.

If it's a long slender torch, try this tip I got from the interwebs: use one of those rubber donor bracelets (Livestrong etc.) looped under the bar and across the front and back ends of the light. I've also put a ring of spare inner tube rubber around the torch as a sleeve so I don't get metal on me...