Dress In Layers
The type of clothing you choose is not enough to guarantee that you stay dry. Also important is that you must avoid sweating during activities. You will learn to monitor how much insulation your body needs to stay warm, but without sweating. By using layers of clothing, you can regulate the amount of insulation and thus regulate your body temperature to the “comfortably cool” state where you are comfortable, but not close to sweating. For example, during the day a musher may continually put on and take off a hat and outer vest as activity levels change. As soon as they stop for lunch, they’ll don the vest and hat to trap the warm air they’ve generated.
When layering, it is very important that there be plenty of room between layers. Layers that are tight and constricting will limit blood flow. Blood circulation is essential to staying warm. One pair of wool socks will keep your feet much warmer than two or three that cut off your circulation and do not allow space to trap air. The same concept applies to your hands. Try liner gloves inside mittens and make sure that there is no constriction and you can easily wiggle all your fingers.
Air and Only Air Insulates
Trapped air is what insulates. When dressing for winter you want clothing with “loft” to hold air. Fabrics include down, synthetic fleece, and wool. This is another advantage to the layering system, as several layers will trap more air than a single thick one.
Wind Protection is a Must
A tightly woven outer layer of nylon or other material will block the wind. It is important that this layer be a compromise between windproof and breathable since you want any perspiration to be able to escape. Many winter jackets have an integral wind shell. During the trip your most important item will be your wind shell, which rarely will you not be wearing. It is imperative that your wind shell has a hood for wind protection and snowfall.