- Base Layer
- Key function: Manage the conditions right next to skin (i.e. keep you dry).
- What to wear? Wool or synthetic underwear, leggings and tops in a weight appropriate for anticipated temperatures.
- Key function: Capture warmth through trapped air. Keep windchill out.
- What to wear? Additional 'baselayers', possibly in a heavier weight; fleece jacket; thicker wool sweater; a combination of everything.
- Key function: Add warmth quickly.
So technically this is a just another mid-layer but when temperatures really drop down, you want to ensure you have a piece that will keep you warm. This is often a jacket stuffed with down or synthetic insulation. It is the piece you'll wear when you're sitting around camp and need to keep your core temperature up. As with sleeping bags, there are pros and cons to each insulation. Down jackets will pack down smaller but synthetics will retain their insulating properties when wet.
- What to wear? Down or synthetic "sweater"
- Key function: Protect you from the elements.
- What to wear? A hard or soft shell that continues to allow moisture to evaporate.
- You will find that many pieces incorporate one or more of the layers mentioned (i.e. a fleece lined soft shell). Always remember that the purpose of layering is to maintain a comfortable body temperature. Do not skip layers that will prevent you from having the ability to get to that next "perfect" temp.
- Start out a little bit cold. If you're heading out on a hike completely warm and cozy chances are you will begin to overheat within your first few kilometers. Keep that extra layer in your pack until you stop for lunch.
- All of these principles apply to your appendages too. Layering hats, mitts and socks is always an option. About those socks though, make sure you don't wear so many your boots are tight. Your toes will get cold quickly that way! Remember, the purpose of the mid-layer is to trap warm air and tight boots don't leave any space for that to happen.
Here's how I layer up for a fall hike:
Base: Icebreaker Sprite 150 Merino leggings, Siren Tank and Hike socks in Light cushion
Mid: Icebreaker Oasis 200 Long Sleeve Crewe, Woolich Fleece
Shell: Rab Charge Jacket or Sawtooth Softshell hoodie, Helix Pants
Hat: Icebreaker Merino Flexichute