Quote History Quoted:
Layering
Silk or polypro long underwear
lined jeans flannel shirt
windproof shell
parka
bomber hat
electric socks
Sorel boots
Basically go search for pictures of fans at a Packers playoff game....
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Pretty close, IMO, but when I'm out snowshoeing down to about -15F I wear:
Silkweight polypro (I like Gen III ECWCS Polartec.)
Midweight Merino or Merino blend shirt (my favorite brand is Stoic, plus both Stoic and Mountain Hardwear make good synthetics for warmer temps.)
Uninsulated Cabela's DryPlus rain pants.
An EMS (Eastern Mountain Sports, a chain similar to REI) Thunderhead rain shell if it's windy.
Nice warm wool gloves, or EMS Ascent Gore-Tex gloves.
On very windy days, a hat. (I'll have sweat streaming down my face at -15F if I wear a hat and it's sunny or calm.)
Darn Tough Merino wool socks (sometimes Smartwool, but I like DT better.)
Sorel Conquest boots.
Outdoor Research Crocodile Gore-Tex gaiters.
Backpack with fleece or down jacket, hat, Merino drawers, extra wool socks, etc.
If I'm camping I have a complete extra set of gear for being sedentary around a campfire - basically heavyweight long underwear (ECWCS or Merino), waterproof insulated Cabela's snow pants (I've snowshoed in these with the side zips wide open for ventilation), ECWCS "bear suit" fiber pile jacket (VERY breathable and fast-drying from body heat), a warmer hat (usually a Nomex Combat Vehicle Crewman balaclava), and Ganka snowmobile mittens or USGI arctic mittens with plenty of extra liners.
Depending on the air temps, wind chill, your load, the terrain, and your acclimation level, you may or may not want to add a layer or 2 to my list. If you're doing more than just shuffling along you WILL sweat so the best bet is to underdress a bit so all that moisture has an easy path to your outer layer where it can be evaporated.
The single most important thing in cold weather is to AVOID GETTING WET. Staying warm is secondary to staying dry. You can survive being dry and cold. Wet and cold will kill you. Cool down before changing out of your hiking clothes or adding layers on top, you don't want to start sweating in your heavier layers because your core temp hasn't normalized yet.