Layering your clothing is all about versatility and efficiency. Instead of dressing in one or two heavy items, layering involves dressing in a number of lightweight items that you can quickly add or remove as conditions change. No matter what you're doing outdoors, you’ll need clothing that helps you adapt to changing conditions and fluctuating levels of activity.
As a rule of thumb, you should expect to be a little chilly when you first start out the day and when you take a break from an activity. After a few minutes of steady movement, your body will start to produce more heat. If you're wearing too many layers to start with, you'll most likely get too hot after about 15-20 minutes of activity. When in doubt, wear your warmest layer when you start your activity, but remove it at the first sign of overheating or perspiration. Also, don't forget your extremities. Unless it’s the middle of summer and you’re close to the equator, always pack a warm hat and gloves, just in case the weather turns ugly.
Building layers is kind of like building a sports team. Each player (in this case, each layer) performs a specific task. Circumstances like weather and activity level will determine whether you need to use all the players or keep some of them on the sideline (in your backpack). There are four main layers: 1) base layer, 2) mid layer, 3) insulating layer and 4) outer layer (i.e. outerwear).
Check out the video below for a quick introduction to layering principles:
Base layer clothing is worn right next to your skin, as a top, bottom, or both. The main purpose of the base layer is to wick moisture away from your body during periods of activity, keeping you dry and providing some additional warmth. Base layers designed for outdoor activities should be made of fibers that pull sweat away from your skin and dry quickly, a process known as "moisture wicking." Depending on your activity level, there are three main base layer weights:
Types of Base Layers
Lightweight Base Layers are best for cool to cold temperatures with high levels of activity, like running, climbing, cross-country skiing, snowshoeing and strenuous hiking. A light base layer may simply be underwear, or it could be a lightweight pair of long underwear.
Midweight Base Layers are best for cold weather and moderate levels of activity, such as slow-paced hiking. This type of base layer is also good for activities with intermittent periods of activity and rest, such as alpine skiing.
Heavyweight Base Layers, sometimes called “expedition weight,” are best for extremely cold and windy, sub-freezing conditions and stationary activities in very cold weather, such as ice fishing, stand hunting or operating heavy machinery in winter.
Base Layer Materials
Polypropylene has been used as a base layer material for decades. It’s lightweight, breathable and dries very quickly. Many people still wear polypropylene long underwear. However, some people dislike the texture of the material, so polyester has generally become more popular. Polypropylene is also more susceptible to retaining odor than other synthetic and natural fibers.
Polyester is probably the most common material used to make base layers today. It’s breathable, moisture-wicking, fast-drying and affordable. Polyester may be blended with other fibers. Spandex adds enhanced stretch. Nylon adds durability. One drawback to polyester is that it may eventually begin to retain body odor, although some brands add an antimicrobial treatment to help maintain freshness.
Silk is a natural, lightweight, breathable and moisture-wicking material that is very effective for making base layers. Although silk is very soft and comfortable against the skin, it’s not as durable as polyester or polypropylene. It’s also more expensive to produce. Silk base layers may require special laundering, so it’s important to check the label before you pop them in the washer or drier.
Merino Wool base layers have become increasingly popular in outdoor sports, starting around the late 1990s. Superfine New Zealand merino wool from brands like Icebreaker and SmartWool is warm, breathable, moisture-wicking and fast-drying. Unlike regular wool, merino wool is soft and quite comfortable against the skin. It’s also naturally odor-resistant and biodegradable, which makes it a popular alternative to polyester. Merino wool is more expensive than most synthetics, however.
Cotton is a comfortable material for general wear, but is not ideal or outdoor recreation. Cotton fibers dry very slowly compared to the other fibers mentioned above. This means that once you start sweating, your cotton base layer will most likely remain damp until you change clothes. If you stop moving in chilly weather and your base layer is damp, you’ll probably experience a chill.
Worn directly over your base layer, the mid layer is designed to offer a slight boost in warmth without adding a lot of extra bulk. Your mid layer could be a long-sleeved polyester or nylon shirt, a lightweight wool or synthetic pullover or a fleece vest. In moderate conditions, you may only need your base layer, mid layer and shell. For hiking and backpacking in cool, dry conditions you might wear your base layer and mid layer, keeping your shell in a backpack. If you start to get too hot, you can simply remove your mid layer and store it in your backpack or tie it around your waist.
Mid Layer Materials
Polyester mid layers are always a good choice because they wick moisture and dry quickly.
Merino wool provides the same benefits as regular wool, without the scratchy, itchy feeling. Merino wool garments make excellent base layers and mid layers.
Nylon is a lightweight, breathable, quick-drying material. A long-sleeved nylon shirt can be a good mid-layer for hiking or backpacking when worn over a short-sleeved base layer. Nylon is more durable than polyester and is sometimes blended with other materials to enhance durability.
The insulating layer is an optional layer worn over your mid layer in very cold conditions. Fleece jackets, hoodies and heavy wool sweaters all make good insulating layers. For very cold conditions, you could even wear a down vest or a down jacket as an insulating layer underneath your shell. Some parkas from brands like Columbia Sportswear actually come with a zip-in fleece jacket for added insulation.
Insulating Layer Materials
Polar fleece is a type of warm, synthetic fabric originally created by the Polartec® company. Polar fleece provides an excellent warmth-to-weight ratio and is most commonly made from polyester, which makes it breathable, moisture-wicking and quick-drying. High-performance fleece, such as Polartec® Wind Pro® and Polartec® Power Shield®, provide additional wind and weather protection for harsh conditions.
Pile fleece is a variation of polar fleece that has been brushed to create a napped surface. Pile fleece, also called brushed fleece, has a soft, fuzzy texture that captures more air and therefore provides additional warmth.
Wool sweaters have been used by explorers to stay warm in the wilderness for centuries. Wool is a fantastic natural insulator, even when wet. However, wool does not dry as quickly as most synthetic fibers.
Down insulation provides the highest warmth-to-weight ratio available in outdoor clothing. In extremely cold and windy conditions, down vests and jackets make excellent insulating layers under a waterproof shell. However, down is often too warm for high-energy activities, such as skiing, snowboarding and snowshoeing.
For more info on down insulation, check out our Down vs. Synthetic Guide.
In wet, snowy or windy weather, your outerwear will be the most important piece of the layering equation. Even if you don’t need a jacket when you start the day, conditions can change quickly. Your jacket and pants will serve as your main protection from the elements, so it’s important to choose outerwear that will keep you dry and block the wind. Options range from waterproof breathable Gore-Tex® hard shells to more breathable, water-repellent soft shells.
Remember that for anything more than low-intensity activity, your outerwear needs to be breathable and well-ventilated. It should also fit comfortably over the rest of your layers. If you buy a new jacket and it fits perfectly with just a T-shirt, you may want to get the next size up so you’ll have room to layer additional clothing underneath.
Jackets and pants labeled water-resistant and breathable provide good protection in mild to moderate weather. Most have a DWR (durable water repellent) coating to shed light rain and snow. Soft shells and waterproof jackets that are not fully seam-sealed fall into this category.
Waterproof breathable shells like Gore-Tex® by Gore, MemBrain® by Marmot and Dry.Q® by Mountain Hardwear provide the best protection in moderate to extreme conditions. In order to qualify as waterproof, a shell must have a membrane and be fully seam-sealed. However, no waterproof breathable shell is going to be “completely waterproof.” With enough water pressure, even the best jacket will leak eventually. For more info on our waterproofing standards, check out the Waterproof Guide.
Old-school rain jackets and rain pants made of a durable, polyurethane-coated nylon are a good example of non-breathable waterproof outerwear. These provide the highest level of weather protection, but also don’t allow internal moisture vapor to escape. For this reason, non-breathable waterproof jackets and pants are usually only used by off-shore fisherman and deck workers that require a significant level of water protection on rough, stormy seas.
Hard Shell vs. Soft Shell
A few decades ago, hard shell jackets and pants were the only outerwear option. Gore-Tex® is a classic example of a time-tested waterproof breathable hard shell. When the weather is really foul, nothing else will keep you as dry. However, hard shells can also be noisy and restricting. Soft shells are made using a stretchy, water-repellent material that provides more breathability and flexibility than a hard shell, along with less noise. Soft shells typically have a smooth, water-resistant exterior and a soft, moisture-wicking interior. This type of outerwear is ideal for activities like skiing, snowshoeing and hiking in moderate conditions with only light rain or snow. For heavy precipitation, however, you’ll be better off in a waterproof breathable hard shell.
A Final Note on Fit
Your outerwear should fit comfortably over your other layers without restricting your movement. For this reason, someone who normally wears a size large shirt may prefer a size XL jacket for added room. Of course, fit varies from brand to brand. Some jackets are cut to provide a little extra room for layering. For more specific information on winter apparel, be sure to check out our How to Dress for Winter Guide.