Moisture drains heat from your feet. Once your feet cool down, it takes a lot of energy to re-warm damp socks and boots. Keep them dry, keep them toasty. Here are some tips to keep feet warm:
Block snow from your boot tops with gaiters or snug-fitting pant cuffs.
Carry a pair of dry socks to change into.
Consider vapor barrier liner socks, a thin non-breathable layer added between a liner sock and thicker outer sock. VBL socks prevent foot moisture from escaping into your boots in the first place and add significant warmth. Plastic bags will even work.
Winter campers should bring their boots (or liner boots) into their sleeping bag to avoid frozen morning footwear. Put them in a plastic bag to keep moisture out of the sleeping bag.
To keep the chill out during breaks or around camp, stand or rest your feet on a piece of wood, which conducts cold much more slowly than snow, ice, or rocks.
Equipped blogger Matt Heid is AMC's gear guru: He loves gear and he loves using it in the field. While researching several guidebooks, including AMC's Best Backpacking in New England, he has hiked thousands of miles across New England, California, and Alaska, among other wilderness destinations. He also cycles, climbs, and surfs.