What is Layering?

If you’ve spent any time in the outdoors, you’ve heard the term “layering.” If you’re new to outdoor activities, though, or maybe if you own a fleece or rain jacket but not much else in the way of outdoor clothing, it may not be entirely clear what this means. How are the layers supposed to work together? Well, we’re here to fix that.

Layering is a wonderfully simple concept. All it involves is combining a few pieces of outdoor clothing in such a way that they can be quickly and easily adapted to a variety of weather conditions or your level of activity. A hike might start in the dewy cold of a spring morning, then blossom into a warm and sunny day; the skies might open up in the middle of your run; you might be generating plenty of heat on your ascent to base camp, but far less once you arrive and stop moving. An appropriate layering system keeps you comfortable in all of these situations.

All you really need are three parts: a base layer, an insulating layer (like fleece) and a shell. Let’s dive right in and talk about what those mean.

Outdoor Clothing Layers

Base layer

OK, so you probably already have a fleece jacket. What’s next? If you don’t already own a synthetic or merino wool base layer, it will make a world of difference. Sure, you can wear a cotton t-shirt underneath a fleece if you’re meeting friends for a couple of drinks, but if you’re going to work up a sweat in the mountains you absolutely need a proper next-to-skin base layer.

The function of the base layer is, primarily, to wick moisture away from the body so it can evaporate, keeping your skin dry. While cotton clothing holds the moisture from sweat or precipitation, leaving you chilled at best or risking hypothermia in colder temperatures, a base layer is integral to staying comfortable in the outdoors. Popular, proven options include:

• Patagonia Capilene. Capilene is primarily polyester, in some cases including the high-performance PolarTec Power Dry fabric and/or spandex fibers. It’s rated from Capilene 1 (lightest) to Capilene 4 (heaviest), and its invention basically created the base layer category. Some competing synthetic base layers include a higher spandex content for additional flexibility, but beware: spandex holds water longer than polyester does.

 

• Smartwool or Icebreaker Merino. Merino wool, a special kind of wool from New Zealand merino sheep, isn’t like the itchy wool sweaters of old; it’s soft and can be worn next to your skin. It breathes and regulates temperature extremely well, in many cases better than synthetics, though it doesn’t evaporate moisture quite as readily. It’s also highly resistant to odor, a major benefit on long backpacking trips or expeditions!

 

Insulation Layer (mid-layer)

The mid-layer is where your fleece comes in. Your base layer retains a bit of warmth, depending on how heavy it is, but thermal insulation isn’t its primary function; that’s what your mid-layer is for. The mid-layer can be a fleece jacket or insulated jacket — down insulation and synthetic insulation each have their merits — and its job is to help you retain heat by trapping warm air close to your body. You have a couple of choices:

• Fleece Jackets. For activity where you’ll be working hard and generating a lot of heat, the additional breathability of fleece helps keep you from being drenched in your own sweat. Modern fleece fabrics like Polartec Thermal Pro are incredibly efficient, which means your fleece doesn’t necessarily have to be all that technical; in many cases, a Patagonia Better Sweater or North Face Osito is as functional a mid-layer as it is a casual piece.

• Insulated Jackets. From the Patagonia Down Sweater to the Nano Puff, insulated jackets dominate the winter clothing world, and with good reason: they’re really warm, usually very good at blocking wind and compress smaller than fleece. They’re also, in most cases, more expensive. Down is the most compressible and warmest, but must be kept dry. Synthetics aren’t quite as thermally efficient as goose down, but insulate better in damp or sweaty conditions and cost less.

 

If you have both, I often like to wear the fleece mid-layer and have an insulated layer in my pack. I can slip the extra layer on when stopping for food or rest, and leave it on if the weather takes an unexpected turn for the worse. After all, being safe in the mountains or backcountry is all about preparation, and failing to bring an “emergency” insulation layer is one of the biggest (and most common) mistakes beginners make.

Shell

Your shell jacket is the all-important protective layer in your system, a thin jacket that’s totally waterproof and totally windproof. These range from $100 waterproof/breathable rain jackets to $600 GORE-TEX alpine jackets, and the difference between each end of that spectrum is a combination of durability, breathability and features. One will be perfect for walking the dog in the rain, one will be perfect for hardcore mountaineering and most of us will fall somewhere in between.

The key here is a waterproof/breathable fabric that allows water vapor and heat to escape the jacket as you perspire; try hiking in one of those $20 vinyl rain jackets and you’ll see what I mean very quickly. If sweat and moisture build up on the inside of the jacket, you’ll end up wet even if it’s effective at blocking rain and precipitation from reaching your body… which defeats the purpose!

Regardless, the beauty of a shell layer is that you can take it off and stuff it in your pack when it’s not windy or raining. They usually compress very small and weigh very little. If you’re going to be outdoors for more than an afternoon, or in weather other than perfect, sunny bluebird days… you can’t do without one.

Real-World Examples

Okay, now that we’ve talked about the different components of your layering system, let’s make some sense of how they all work together. What are some typical scenarios and outdoor conditions for one or two of the layers, or all three?

Base Layer + Shell. This is the typical peak-bagger’s setup. Let’s say you’re going to be hiking 12 miles round-trip from the trailhead, to the top of a mountain and back down the way you came. You have a small daypack, and you’re not planning to spend too long on the summit. Perfect. Most times, unless it’s savagely cold or windy, I’m fine hiking uphill in a base layer alone. Put the shell on when you reach the top, to cut down the inevitable wind, and you can keep it on for the descent.

You’ll need to have an insulating layer in your pack, as “insurance,” but it may never come out. The key here is high output — you’re generating enough heat that a fleece or insulated jacket would be overkill. If you’re working so hard that wearing even a waterproof shell becomes uncomfortable, as in trail running, a thin wind layer may suffice.

Base Layer + Fleece. This is almost the opposite; it assumes you’re not generating enough excess body heat to stay warm, and you need a fleece jacket to insulate your body. It also assumes little wind and no precipitation.

However, since these conditions describe MANY typical outdoor experiences — a hike on moderate terrain, a fall camping trip, a barbecue, walking your dog, et cetera — you may find yourself in this combination more often than anything else. After all, you won’t need your shell unless it’s raining or particularly windy, and your fleece won’t roast you alive unless you’re really working up a sweat.

Base Layer + Fleece + Shell For lack of a better word, this three-layer setup is the standard. Backpacking, hiking in suspect weather, multi-pitch climbing in the cold, basically any multi-day trip away from the comfort of home, this is what you want to bring. You’re covered for either of the scenarios above, and if you need both warmth and weather protection, you can wear all three layers. This is a versatile, practical approach to being comfortable in the outdoors.

Base layer + Fleece + Insulated Jacket + Shell What if it’s really cold, so cold that you’re not sure a fleece will provide all the warmth you require? What if you need to wear a thin fleece mid-layer while leading a route, but that’s not nearly warm enough when you’re on belay? The answer is to carry an additional piece of insulation, usually a down jacket or synthetic-fill jacket.

Climbers often carry a belay jacket specifically for this purpose, a large puffy that goes over the shell layer and harness for belay duty. Unless it’s raining, this works fine. Likewise, I’ll often carry a lightweight insulated jacket in my pack on backpacking trips, which I put on when it’s time to make camp. The only thing worse than leaving the tent for a frigid, 3AM pee break is doing so without enough warm layers!

Conclusions

If you have a good fleece jacket but no shell, or vice versa, purchasing the corresponding garment will give you a ton of versatility for the next adventure you dream up. If you have both, but not a next-to-skin layer, you’re almost there! Pick up a nice merino base layer and you’ll see a world of difference performance-wise. In any event, this is the way outdoor clothing was meant to be used, layered together to form combinations that keep you safe and comfortable no matter what crazy weather comes next.

More expensive options will likely last longer and perform better — especially with shells — but your level of interest will determine the best bang for your buck. The more time you spend outdoors, especially on extended trips, the more justified a large investment becomes. There really is a difference between a $20 base layer and an $80 base layer, after all! If you’re not sure which option is the best fit for you, stop in your nearest store and we’ll be happy to help you choose what’s best for you.