That can be a difficult problem to solve. I assume you’re talking about alpine skiing here, for one thing. And properly fitted alpine boots should fit quite snugly, not leaving much room for thick, warm socks. Still, there are three ways to attack cold feet when skiing.
One, wear the right socks. Wear a thin liner sock made from silk (REI Silk One Liners, $6.50; www.rei.com), wool (SmartWool Merino Liners, $9.95; www.smartwool.com), or a good synthetic (Patagonia Capilene Liner Socks, $11.50; www.patagonia.com). These will help trap warmth near your skin and keep your feet dry. Over the liners, put on a good-quality ski sock. Don’t try to pack your boot full of socks, as that will simply reduce circulation and worsen things. SmartWool Medium Cushion Ski Socks ($18) are good, so too are Wigwam Outlast Ski Socks ($14; www.wigwam.com). The Wigwam socks are interesting, using a material (Outlast) that actually stores, then releases heat on an “as-needed” basis. It’s something of a miracle fabric, although is still little-known.
Two, you can also add some insulating insoles that will help keep cold from coming up through the bottom of the boot (the metal bindings on skis are wonderful cold conductors). Insolator Insoles ($8; www.foxridgeoutfitters.com) come in quarter- and three-eighth-inch versions, and should fit right inside your ski boot.
Your final option is to actually heat the socks. Cabela’s sells battery-heated socks for $20 (www.cabelas.com) that run off two D-cell batteries. The battery pack attaches securely to the top of the sock, under your ski pants, to stay in place.
So there you go. Happy skiing!