Layering as it is practiced by all of the people I know who use it consists of 1-3 layers of light long sleeve silk or polypropylene or capilene. Think Under Armor type of shirts, except a little bit more loose in general. Then these people wear 1-2 layers of heavy insulation like wool or fleece. They cover that up with 1-2 layers of wind/water resistant jackets or pull overs. That's a great combination if you plan on standing around all day. However, if you plan on doing something physical and generating heat you are going to sweat, even if the windchill is below zero.
How can I blast a time tested system? How can I say that it is not the best cold weather clothing system? Experience. Nearly every time I go on a winter hike or cold weather outing with less experienced people we have to stop in the first twenty minutes and they take off clothing.
I do not know the name of the person who coined the name "action suit" but I discovered it on my own in New Hampshire's mountains and with a little help from friendly corporate softshell advertising. It works like this: wear one combination of clothing that consists of relatively few layers and commit to wearing them all day long even if it gets hot. Those layers hopefully have venting zippers and hoods so that you can cool off while working hard. Then have one (just one) layer that you put on when you stop to rest or cook or belay. This is generally a belay parka and puff pants.
My preferred system which I have now used in three states, two countries, and three time zones, hiking, ice climbing, skiing, bicycling in the winter, and up to 23,000 feet is this:
- A full body softshell bib made by Ragged Mountain that I bought used that they don't make any more. Mine has two chest pockets, leg zippers to chinch it or loose it near your ankles, a half moon zipper for using "the loo", and a two way zipper in the front so I can zip the bottom part open if I have to go or zip the top part open if I am too hot. Here is a similar suit that is twice the price of what I paid.
- The Patagonia R1 Hoody! I think I average blogging about this once every two months. Anyway it is an extremely breathable yet insulated hoody with a half zipper and partial face mask. It also has hand extensions with thumb holes. The nice thing is that if it really warms up I can unzip the chest and take the hood off and vent a lot of heat. As some of my videos in Pakistan in the tents at camp two and three show. I even have a spare that still has the tags in case they quit making it. This and the bibs make up the core of my system.
- A pair of gloves. Always a pair of gloves they are light and do wonders to keep your hands a little warm and out of the wind. The actual gloves vary based on the temperature, wind and activity. I have four different pairs that I rotate through depending on the activity. Although I am not an expert on gloves and I can't wait to have $160 to drop on a pair of nice insulated leather ones...
- Depending on the temperature I will either wear running shorts, half tights, or thick full length 2008 Patagonia nordic skiing tights that they don't make any more under the bibs.
- If it is cold I will wear a long sleeve under the R1 Hoody. I have two Nike long sleeve shirts that are really light and fit very nicely. I also have some compression tops similar to Under Armor but I usually feel my motion is restricted when I wear those.
- Occasionally I wear my Mountain Hardware Alchemy jacket over the bibs when it is cold and windy. More often than not though it is too warm. This is a tried and true jacket that has been around for ten years and will probably be here another ten.
- When the temperature is too warm for my parka I carry a three ounce 2007 Marmot Ion jacket. It's mostly wind proof and water proof. I will start sweating when I wear it most of the time but it really keeps the wind off and is absolutely worth the three ounces of weight. I carry this in the summer rock climbing and cycling too. Basically it's the one thing that is guaranteed to be in my pack on any trip in any season.
- For a belay/rest/cooking parka I have a Mountain Hardware Sub Zero Hooded Jacket. It is not the warmest parka out on the market but has always been plenty warm up to 7000 meters. I like it because the waist cut is a little higher than many jackets so I can get to my harness. It also has a ton of pockets including an inside pocket big enough for a one liter Nalgene or thermos. It also has an insulated hood which is a must.
- I have a pair of Mountain Hardware Compressor pants which are synthetic and again not the warmest insulating pants on the market. They have full side zips so I can put them on while standing and wearing crampons without lifting my feet off the ground. One note on why I have so much Mountain Hardware stuff is that the stuff just fits me really well. The sleeves are the right length for me.
- A pair of thick mittens. I don't always carry these for skiing or short hikes but anything more than a few hours or in serious weather will see a pair of either Outdoor Research Alti Mitts or Valandre Oural (down) mittens in my pack because I like my fingers.
- When it is really cold I wear the Outdoor Research Gorilla balaclava. It is very warm and windproof and can be worn with my goggles or with my sun glasses.
I will skip the discussion on footwear because that could take up a whole post. So that is my action suit. You can see that in general there are not many layers, just several functional layers with hoods and chest zippers so that I can air condition myself or turn up the heat. Is there room for improvement? Yeah, any clothing system will vary based on the weather and more importantly in my case the budget. This system and these articles of clothing have served me very well so far so I do not expect any big changes to my system in the next few years.
One last comment I have is about hoods. When it comes to winter clothing hoods are a must. You can put it on or take it off in several seconds and you do not have to worry about putting it in a pocket or your backpack. You lose a lot of heat through your head. Protecting your neck and head from the wind and cold can keep in a lot of heat. This is again why the R1 Hoody is so amazing. When fully zipped up only my nose and eyes are exposed. When unzipped my chest, head and neck are all exposed and I cool off rather quickly.