Many years ago, I spent a winter at a military base near Chicago. The wind from the Great Lakes made the place miserable, often the wind chill was below zero. Every morning we had to get up and march to chow in the dark. We did not have good cold weather gear and put on everything we had. We did not have long underwear. Our dress consisted of fatigues, field jacket with liner, and a cotton hat. We would then put on our heavy dress overcoat and use a towel for a scarf. We just had thin leather gloves and no decent headgear. By the time we had marched a mile to the chow hall we were frozen and sometimes on the verge of hypothermia
Since then I have learned a lot about how to dress for cold weather. Now since many of you know that I live in California, you may wonder how I learned. Well I live in the foothills of the Sierra Nevada Mountains and have spent time near Lake Tahoe and Truckee which have lots of snow and gets very cold.
In cold weather, wear multi layers. You should start with a good base of long underwear. Avoid the cheap cotton long underwear sold in the discount houses. Fleece, polypropylene, or wool retains most of their insulating properties when wet. They are the best choices. Cotton loses its ability to insulate when wet and may cause you to suffer from hypothermia.
You should then have a good intermediate layer. The purpose of this layer is to keep heat in and cold out, which is accomplished by trapping air between the fibers. This layer should consist of a shirt and pair of pants made from fleece, polypropylene, or wool. You should never wear blue jeans. Cotton holds moisture and loses its insulating properties when damp. A friend of mine who ran cold weather survival classes said that based on his experience he wouldn’t take students on a cold weather trip who wore jeans or cotton. As an option (one I prefer) you may want to add a vest.
The outer layer, pants and jacket should be water/wind resistant, but breathable to let perspiration evaporate. It is best if this layer has a hood.
Wear a good pair of gloves or mittens and do not forget to cover your head. In some circumstances, you can lose up to 50% of your body heat through your uncovered head and neck. A fleece neck gaiter (like a collar) or facemask is necessary on very cold days. Mittens, in general, are warmer than gloves, but offer you less dexterity. Consider the type of activity you’ll be doing. Personally, I like wool gloves with a removable waterproof outer shell.
Keep your feet warm with two pairs of socks and a good pair of boots. This is a minimum for cold weather. If you are in wet weather or snow, make sure your boots will repel moisture.
The reason that layering works is that it gives you the ability to control your body heat. Layering gives you the flexibility to add or remove layers, depending on the weather and your activity. If you are to warm, you will sweat and collect moisture in your clothes. Layering also traps air between the layers providing additional insulation.
I am still a big believer in wool, there is a reason our ancestor depended on it. Untreated wool still has the fatty lanolin from the original animal and can be almost waterproof. Even fine wools give you some protection. Wool fibers are highly absorbent and can soak up around 20% of their weight in water before it starts to leak through. Sailors and fishermen in extremely wet and cold climates have traditionally worn tightly woven sweaters of raw wool for their protection. Wet wool will keep you warmer than other fabrics when wet, but you will still be cold until it dries. The best thing is to stay dry and avoid hypothermia.