Insulating Layer --
Warm, Lightweight & Compact

The insulating layer of your outdoor wardrobe, as the name suggests, will be crucial in keeping you warm in cold weather. It is lightweight, non-bulky and dries quickly. What magic fabric does all that? Will it be hard to find? Expensive? Surprisingly, you might already have an article of this magical, easy to find, inexpensive clothing in your closet right now.

When Will I Need It?

In warmer weather you likely will not need this layer at all. In fact, you will want to wear a loose-fitting wicking layer to allow for evaporation of your perspiration as you hike. The evaporation will actually help you to cool.

However, in the unpredictable weather conditions of spring and fall, and ALWAYS if you are hiking above the tree line, you will want to have your insulating layer with you. Mountains produce their own weather systems and you never know when you may be exposed to a cold rain shower or even snow fall.

Your insulating layer takes up so little space and is so light that there is no reason not to have it with you always. So what does this special insulating layer consist of?


Your best choice for this layer is fleece or micro fleece. This amazingly lightweight fabric is very warm and helps to keep body heat next to your body where you want it. If exposed to water, it doesn’t absorb it well…a definite advantage for our purposes. The moisture it does absorb will dry very quickly.

My insulating layer consists of:

• a lightweight jacket
• a pair of mittens
• a hat
• 2-3 pair of socks


Some people prefer a vest rather than a jacket, allowing arms to move more freely. Fleece jackets and vests come in several different weights. Of course, the heavier and denser the fleece, the warmer it insulates. Micro fleece is lighter and less bulky than fleece. Also, some garments include a layer of windproof material between two layers of fleece.

I find that using polypropylene as my wicking layer, a lightweight fleece suits me just fine in most conditions. If I am chilled, I can always use my short sleeve polypropylene shirt from my wicking layer as added insulation under my fleece.

Give some thought to how cold natured you are and how warm you get when you hike. Also, think about where you will be hiking and the likely weather conditions. A little experimentation will show you exactly the level of insulation that you need.


In colder conditions, I carry a pair of fleece mittens. I usually don’t need these on the trail except in the coldest conditions and even then only early in the morning. However, mittens can feel quite cozy after the sun goes down and your body begins to cool from the days hike. Also, early in the morning they are a welcome respite for my cold fingers, especially when paired with my silk glove liners from my wicking layer.


A hat is a hiking necessity. I’ve seen hikers in everything from baseball caps to the old wool stocking caps.

In warmer weather, I recommend either a baseball cap or a wide-brimmed hat to shade your face from the sun…and even a light rain shower. You can even find a dessert-style wide-brimmed hat that has flaps to cover your neck as well.

In colder conditions, I like a fleece hat. I consider it a prominent part of my insulating layer. Keeping your head covered will help tremendously in keeping you warm.

The head has many blood vessels that bring the blood close to the surface of the skin. Blood that comes close to the skin’s surface cools rapidly, making you cooler. An extra benefit of a fleece hat is that it is soft enough to sleep in at night, when I tend to be the coldest.


My one departure from fleece in my insulating layer is my socks. I wear wool socks over my wicking layer of nylon or polyester lining socks. This gives the liners somewhere to deposit the perspiration that it wicks away from my feet keeping them dry and warm. Additionally, should my feet get wet from crossing a stream or hiking in the rain, wool stays warm even when wet.

I always keep a spare pair of wool socks in my sleeping bag to wear while sleeping. Having warm feet just helps me sleep better. Itchy wool isn't a problem because I always use nylon or polyester socks between my feet and the wool--even when sleeping.

That rounds out our insulting layer. We can now complete our clothing inventory by looking at our windproof/waterproof layer.

Return from Insulating Layer to Backpacking Clothes

Return from Insulating Layer to Ultralight Backpacking