A round-up of everything you wear, from head to toe, with some commentary on my personal preferences.
Head, Face, and Neck
You likely won’t need every square inch of your head and face covered while winter camping, but if you plan on heading above treeline in cold, very windy conditions, definitely have the four essentials—liner balaclava, hat, face mask, and goggles (plus a good hood).
What I wear: Thin polyester liner balaclava, light WindPro fleece beanie, Seirus Masque, Smith OTG goggles.
You’ll first want a super-comfy, warm, properly-fitting base layer. Then at least one mid-layer (two with a vest), and finally an outer layer. A large-fitting, extra-warm down parka can go over everything for maximum warmth. Fit is extremely important when you’re layering garments; make sure your system works well together
What I wear: PowerStretch zip-neck base layer, wind-proof fleece vest (when necessary), a mid- to heavyweight fleece jacket (no hood), Gore-Tex outer shell, and an extra-warm down parka (a.k.a. ‘Big Puff’).
Liner gloves and some heavier, warmer handwear for going over them. Mitts are much warmer but compromise dexterity. Fit matters a lot when it comes to finger warmth; try out multiple brands and styles.
What I wear: PowerStretch liner gloves and warm, XL mitts with removable liners and waterproof shell (most of the time)
When you’re moving, you will seldom want anything more than a base layer and outer layer. Anything more usually leads to overheating unless it’s severely cold. In camp, a pair of puffy zip-on pants are really nice, especially since you can take them on and off without removing your footwear.
What I wear: PowerStretch bottoms, Gore-Tex bibs, side-zip Primaloft-insulated pants.
Liner socks and extra warm socks inside warm, insulated footwear. Consider using vapor barrier liner socks for extended trips. You’ll need pretty rigid boots to wear most crampons, though more flexible traction options are available. Gaiters are usually needed, especially if the snow is deeper than your boot-tops.
What I wear: Polyester liner socks, vapor barrier liner socks (for any multi-day excursion), thick wool socks, plastic mountaineering boots or other stiff winter boots, heavy-duty gaiters with reinforced cuffs and a wide Velcro seal.