We've all been there, you start out your hike in the sunshine and finish in a downpour. Your hiking clothes should be like an onion. Peeling off layers until you find your optimal setup depends on weather and your outdoor activity.
Layering is an important skill to have in your quiver of outdoor knowledge. There are three main layers that you should be familiar with, each one with a specific purpose.
This layer sits right next to your skin. Because it is meant to wick away or absorb moisture during activities, this layer should never be cotton. Cotton will hold moisture against your skin and keep you cold. Your base layer should be lightweight and made of a synthetic material or natural fabric like merino wool. Base layers are light enough that you can wear them for indoor activities, but not warm enough to be worn solo outdoors in the spring. A base layer should fit snugly against the skin, but not so tight to restrict movement.
This layer goes on top of your base layer. Think of your mid layer as your insulation from the cold. Depending on the weather this could be a lightweight fleece or a 600 fill down jacket. This layer is meant to trap air during your activities and keep you warm and toasty, so the fit should be close to the body, but not so close that you can’t move freely. It never hurts to throw an extra fleece in your pack as a backup mid layer should you or someone in your group get cold. A down vest also works great as a mid layer to keep your core warm while allowing your arms full mobility. If the weather isn’t terribly wet, some mid layers will suffice as an outer layer.
Wearing a mid layer as an outer layer while ski touring will prevent your outer layer from collecting condensation from sweat while you skin up. You'll be warmer and dryer on the way down.
This layer is your protection from the wind, cold, and/or rain. Look for an outerwear layer that is waterproof, windproof, and also breathable. GORE-TEX fabric is a great option for those looking to meet all three requirements in one jacket. It’s unlikely that you will find an Outer Layer that will fit all of these needs for every sport you do.
Experiment with what layers work for you during your outdoor activities. Just remember that technical fabrics work best when properly cared for.