Having a reliable clothing system is essential for both comfort and safety. A good system should handle a wide range of weather extremes without filling up your pack. Everyone is familiar with some form of layering system. The questions are: how many layers are necessary to maintain comfort in all conditions and what should those layers be?
Dressing for hiking and mountaineering can be remarkably simple if you follow a few basic principles. Surprisingly only a few layers are needed if they can provide a wide comfort range. The outdoor industry is constantly dreaming up new names, components, and slogans. Beware of the influence of heavily marketed ideas.
Below is our recommendation for a lightweight clothing system that works.
The Concept of Layers:
Your most important layer and worth repeatingno piece of outdoor clothing is as important as your next-to-skin layer. This is the layer that will need to handle maximum heat and moisture generated by strenuous activity, and keep you comfortable during periods of inactivity as well. Base layers should be loosely knit, thin, and capable of providing the widest possible comfort range.
Keep in mind that two thin base layers combined will provide a far wider comfort range than one thick layer. One short sleeve and one long sleeve shirt is a popular method. Overheating your body saps strength and endurance. Beware of base layers that are tightly knit or otherwise designed to be windproof, as they cannot provide the comfort range necessary for this most important layer.
A light shell layer that is breathable, yet windproof will add a surprising amount of warmth without compromising freedom of movement. Hard Shell or Soft Shell in design, it is important that this layer does not include fleece or other wicking or insulating materials. These materials will only prevent your base layer from performing optimally and reduce the versatility of your system.
Puffy, lightweight, and packable. This is your warmest layer and is usually worn during periods of inactivity or any time you're cold (breaks, lounging, belays, on summits, in camp, etc.). Goose Down or Primaloft insulation quilted with lightweight nylon shell fabric is ideal. Maximum warmth for a given weight is the goal. Snug well-tailored cuts are generally warmer than loose baggy cuts.
This shell layer, preferably of a waterproof/breathable fabric, is for rain and snow. It usually stays in the pack until conditions get particularly ugly, so it should also be lightweight and packable.