minus 33 merino wool clothing, Layering 101: Outer Shell Layer

Layering 101 with Minus33

Layering 101 with Minus33 Merino Wool!

Layering is a great way to thermoregulate your body as weather conditions and activity levels change throughout the day. Whether you’re going for a quick day hike, or taking on a thru-hike, having the right layers can make your trip more enjoyable and also keep you protected against hypothermia or heat exhaustion. There are generally three to four pieces used in a good layering system: base layer, mid layer, insulating layer, and outer shell layer. Each piece of your layering system has a different purpose, starting with your Base Layer.

Base Layer

Your Base Layer is your second skin. This is your first layer on and your last layer off. Your base layer should be: thermal, moisture-wicking, breathable and comfortable under all conditions. Merino wool base layers provide excellent moisture management through superior wicking and fast-drying capabilities. Merino wool is also naturally odor-resistant, and antimicrobial. Wool is a great natural insulator, and when it does get wet, it will still insulate you better than other fabrics. It is super soft and comfortable against the skin.
Remember --- Never wear cotton in the outdoors - cotton does not dry quickly and staying wet can put you at risk of hypothermia.

Mid Layer

The Mid Layer is your second layer. It should provide extra insulation while still being breathable. Zips are often used in Mid Layers for easy removal and replacement, as well as helping you vent without completely removing the layer. Merino wool works great as a Mid Layer, too. It is plenty breathable and will work great to regulate your body temperature. Its warmth to weight ratio is excellent, allowing you to easily shed your mid layer and pack it away as conditions change.

Insulating Layer

The Insulating Layer is used when the weather is colder. It is a second breathable Mid Layer that provides extra warmth. Like the Mid Layer, it too can be easily removed and packed away as conditions change.


Outer Shell Layer

Your Outer Shell is your last level of defense against the elements of nature. It should be wind and water resistant, packable, and breathable. Many shells have vents and waterproof membranes for added breathability.



For the coldest days footwear can have layers just like the rest of your body. Start with a liner sock, then a loftier sock, and finally a good boot over the top. Wool socks are the way to go. Make sure you have enough room in your boots to move your toes - this helps your blood circulate.
Pro Tip: Carry a spare set of socks so you can switch for a dry pair if your feet do get wet.


A good hat may not always be enough - for colder temperatures, consider a balaclava or neck gaiter that will cover your neck and ears. The removal or partial removal of your head gear is a great way to cool down fast when overheating. You may also desire eye protection such as goggles or sunglasses.



Add some merino wool glove liners for extra warmth under a waterproof glove or mitten. Just like your feet, make sure your hands have enough room to move and keep your blood circulating.

Putting It All Together

Layering systems are customizable and interchangeable. Your layering system will vary based on activity, season, and your personal comfort. Proper layering of your garments is incredibly important and in extreme cases may save your life. Consider your activities carefully and plan for the unexpected. Not everyone will layer the same. Some people's hands and feet get colder easier. Some people just plain run hot. You may need to experiment to figure out what will work best for you and your activities. A good layering item in your pack is better than one left at home. Before heading out, you should always consider: the weather forecast, how long you will be out, and whether you will be stationary, active, or a combination of both. Those are the main factors you need to consider when selecting what to bring on your next adventure. Happy layering!