Layering is the secret to staying warm, dry, and comfortable when you’re exercising or doing anything outdoors—even commuting to work. Let’s look at how to get started.
The Three Layers of Clothing
There are three kinds of clothing layers:
- Base layers: These are worn next to the skin. They are the base of the layering system. Their purpose is to wick sweat away from your skin when you’re sweating and provide you with a little warmth. In really hot weather, you might only need a base layer, but in all other weather, you’ll wear one underneath the other layers.

- Mid layers: These are worn over base layers. They do most of the work of keeping you warm and maybe keeping the weather out a little bit. They’re by far the most variable kind of layers. Everything from a light fleece to a puffy down jacket is a mid layer. In bad weather, you’ll probably wear more than one.

- Outer layers: These are the weatherproof layers you wear over everything else. Their job is to keep the wind and rain off the mid layers so that you stay warm and dry. They include everything from light rain shells to heavy offshore sailing waterproofs.

Mixing and matching layers is the key to staying comfortable whatever the weather and whatever you’re doing. The best thing about layers is that, unlike the old heavily insulated overcoats and ridiculous wooly jumpers, you can adapt as situations change.
If you’re out hiking and the morning starts off cold you can wear a base layer and two mid layers. As the weather warms and you get more active, you can strip off one mid layer to keep at a comfortable temperature. If the weather turns for the worse you can add the mid layer back on and put on an outer layer; but, if the weather turns for the better, you can take off the other mid layer and bask in the sunshine in just your base layer.
Choosing a Baselayer
A base layer is often the most critical layer you wear. Choose the wrong base layer and whatever you put on top won’t make a difference.
There are three main kinds of base layer: T-shirt tops, long-sleeved tops, and leggings. T-shirt tops are what you’ll probably wear for most weather. Long-sleeved tops and leggings are for when things turn cold and wet.
The most important thing about base layers is the material they’re made from. Since they often look a lot like cotton T-shirts, a big mistake people wear starting is actually wearing cotton T-shirts. Cotton kills in the outdoors. While it’s okay for wearing around town in the summer, once it gets wet (either from sweat or rain), it loses all insulating properties.
Seriously, avoid cotton when you can.
This leaves two primary materials you can choose from for base layers: merino wool and synthetic fabrics.
Merino Wool
We’ve looked at depth in merino wool before, but it’s a fantastic material for a lot of reasons. Here’s what you need to know:
Pros
- Merino wool keeps you warm when it’s cold and cools you down when it’s hot.
- It wicks sweat away from your body and stays warm even when it’s soaking wet.
Cons
- Merino wool is a lot more expensive than other materials.
- It’s also fragile and wears down quicker.
Synthetic Fabrics
The other option is polyester and other synthetic fabrics:
Pros
- Synthetic base layers are the cheapest.
- They’re great at keeping you warm and wick sweat away from your body.
Cons
- Might keep you too warm in warmer weather.
- Smell awful after one use.
Most people have a mix of different base layers and pick the one they need based on the conditions (and the state of their laundry basket). I have a mix of merino wool gear from Icebreaker and cheap, no brand, synthetic tops.
Choosing a Mid Layer
Mid layers do most of the work of keeping you warm, so there’s a wide variety from which you can choose. Think wool sweaters, fleeces, down jackets, vests, and the like.
The thicker a mid layer is, the warmer it’s likely to be. However, it’s usually better to wear two slightly thinner mid layers than one thicker one: it gives you more flexibility.
Like with base layers, you have a choice of wool and synthetic mid layers. Cotton still kills. While I’d encourage you to have at least a few wool baselayers, the case isn’t as clear cut with mid layers. Fleeces and synthetic puffy jackets are pretty excellent at keeping you warm.

Ideally, you’ll have a couple of different mid layers in your closet, and you can choose the mix that’s most appropriate for your activity. My go-tos are a light wool sweater, a heavier fleece sweater, and a down jacket. If it’s really cold, I’ll wear all three, but usually, I wear either just the light wool sweater or the fleece sweater on their own or under the down jacket.
One thing to consider with mid layers is how easy they are to carry. One reason I love my down jacket is it’s warm but compressible and weighs next to nothing. It’s effortless to just throw in my pack or car and forget about. That isn’t as easy to do with a wooly sweater.
Choosing an Outer Layer
Outer layers are the weather protection that goes on top of everything else. They’re for keeping the wind, rain, and blowing snow out.
There are two main kinds of outer layers: soft shells and hard shells.
Soft shells are lightweight synthetic jackets that are wind- and water-resistant, rather than windproof or waterproof. This makes them much more comfortable and, since they’re not fully water-resistant, they’re also breathable; your sweat can evaporate off.

Hard shells tend to be heavier synthetic jackets that are fully windproof and waterproof. The extra bulk and weight make them less comfortable than soft shells. Also, since they’re waterproof, if you are active enough to sweat, your clothes will get wet and stay wet.
In almost all situations, you’re better off with a soft shell. You should only really wear a hardshell when you know you’re going to be fighting off near constant water—like when you’re hiking in a steady rain, sailing, or skiing.
Putting It All Together
Layers make it a lot easier to stay warm and dry than the old school method of finding the biggest, heaviest, warmest jacket you can and hoping it works. Whether you’re commuting to work or hiking the Pacific Crest Trail, the same principals apply:
- Pick a comfortable wool or synthetic base layer. If you’re in the city on your way to work, a cotton T-shirt or shirt is okay.
- Layer one or two mid layers over the top. A combination of different layers works great and lets you adapt to whatever the weather does.
- If the weather looks a bit wet or windy, top it all off with a soft shell. If things look hairy, either stay indoors or grab a hard shell.
You should adjust your layering whenever you need to. As you board a hot subway, ditch the second mid layer. When you come back out to the streets, put it back on. Leave your soft shell in your bag until the wind or rain picks up then throw it on. This is why more layers are generally better: it means more flexibility and more comfort, whatever the weather does.