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EducationLayering

The Science of Layers

Welcome To Our Short Course On Layering

Ready to Layer?

Thank you for joining us in The Let’s Adventure Academy Course Library! 

This free short course is brought to you by The Lady Alliance Foundation – helping change the face of leadership in the outdoor industry. 

The content gathered for this course was collected through research online, as well as personal experience shared by our team of chapter coordinators and board members. We wanted to especially recognize REI as one of our main sources of information and imagery for this short course. We love learning from REI – you can do so here!

Just by being here, you’re helping The Lady Alliance Foundation make a difference. Our collection of free and short courses are to be enjoyed by all to help build confidence in the outdoors. 

This course is one of our free courses. If you are able to support The Lady Alliance Foundation through a donation, you can do so here. Every dollar helps! 

However we want to ensure that the majority of our education material is accessible to everyone. 

We thank you for your support of our foundation, and hope you enjoy the next few lessons on layering! Don’t forget to send this course to a friend to help inspire further education in the outdoors!

Much love, 

The Lady Alliance Foundation

Layering Basics 

How To Layer

When you step outdoors, layering will become the make or break for your adventure. Layering allows for you to regulate your body’s temperature needs, help you cool faster, stay warm, keep dry, and in more intense situations – stay alive. 

To understand layering your clothing for outdoor activities, you need to know the function of each layer:

  1. Base layer (underwear layer): wicks sweat off your skin
  2. Middle layer (insulating layer): retains body heat to protect you from the cold
  3. Outer layer (shell layer): shields you from wind and rain

Even if you don’t wear all three layers right from the get go, it’s a good idea to have all the layers with you. Part of the art of layering is to know when to utilize each layer, and when to remove layers when needed. 

Base Layer: Moisture Management

Your base layer’s job is to move perspiration away from your skin, aka “wicking.” In cool or cold conditions, wicking long-underwear-style base layers are needed to keep your skin dry. That’s essential because it helps to keep you from becoming chilled or worse—hypothermic.

Base layer materials: You have a wide range of fabric options, including synthetics like polyester and nylon, or natural fibers like merino wool and silk. You do not want to use cotton. Though there are subtle differences in wicking and drying for each material, and in odor retention and durability, a lot people simply go with their personal fabric preference. 

Base layer weights: Lightweight, midweight and heavyweight are your three main options. There is also “ultralightweight” on one end of the spectrum or “expedition weight” at the other if you journey into more technical or advanced layering needs. Generally, heavier (thicker) fabrics keep you warmer, though that’s not really the primary purpose of a base layer (wicking is).

Middle Layer: Insulation

The insulating layer helps you retain the heat that’s radiated by your body. The more efficiently this layer traps that heat, the warmer you’ll be.

Middle layer materials: Just as with base layers, you have a broad range of options, both synthetic and natural. In general, thicker (or puffier) equals warmer, though the efficiency of the insulating material is also important. Below are some common middle layer materials, though other options, like wool and wool-blend tops, are also available.

Thanks to REI, here are some of your primary choices for middle layers:

Polyester fleece: Available in lightweight, midweight and heavyweight fabrics (sometimes marketed as 100, 200 and 300 weight), fleece stays warm even if gets damp, and it dries fast. Fleece also breathes well, so you’re less likely to overheat in it.

The flipside of breathability, though, is that wind blows right through, which can steal warmth. That’s why you need to have a shell layer with you if you’re going with a fleece middle layer. (Another option is to wear wind fleece, which includes an inner wind-blocking membrane.)

Down insulated jackets: Highly compressible for easy packing, down offers more warmth for its weight than any other insulating material. The efficiency of down is measured in fill power—from 450 to 900. Because down is always inside a shell material, down jackets also offer some water and wind resistance. The drawback to down is that it loses insulating efficiency when damp.

Synthetic insulated jackets: Synthetic insulations have long tried to mimic down’s efficiency, coming closer to that standard every year. And, while synthetics don’t compress as well as down, they’re a popular option for rainy conditions because they retain insulating ability when they get damp. And, like down, synthetic insulation is always inside a shell material that offers added water- and wind resistance.

The key with your insulation layer is air, no matter what fabric it is, is that trapped air keeps you warm. If you have a bunch very tight layers without any air in between, you won’t be maximizing your warming efficiency. This is why something like down jackets are a popular insulating layer. 

Outer Layer: Rain and Wind Protection

The outer layer (or shell layer) protects you from harsh weather such as wind, rain and snow. Shells range from pricey mountaineering jackets to simple wind-resistant jackets. Most allow at least some perspiration to escape, and virtually all are treated with a durable water repellent (DWR) finish to make water bead up and roll off the fabric.

Your outer layer, or outer shell is an important piece in stormy weather, because if wind and water are allowed to penetrate to inner layers, you can get seriously chilled.

Thanks to REI we can learn about shell categories. Shells can be lumped into the following categories:

Waterproof/breathable shells: Your most functional (and expensive) choice, this type of shell is your best option for full-on squall conditions. Generally, pricier equals drier, though higher priced shells are often more durable as well.

Water-resistant/breathable shells: These are more suited to drizzly, breezy conditions and high activity levels. More affordable than waterproof/breathable shells, they’re typically made of tightly woven nylon or polyester fabrics that block light wind and light rain.

Soft shells: These emphasize breathability. Most feature stretch fabric or fabric panels for added comfort during aerobic activities. Many combine light rain and wind protection with light insulation, so they in effect combine two layers into a single jacket.

Waterproof/nonbreathable shells: These bare-bones shells are okay for rainy days with light to no activity (e.g., fishing, spectating). They are typically made of a coated nylon, which is water- and windproof. If you exert yourself while wearing one, you’ll probably end up saturating your underneath layers with perspiration.

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Lesson 3: Layering for Summer

Ready For It All

Even during the summer, the weather can turn quickly. Especially when hiking or out and about it is important to be prepared for all weather. Remember, weather expectations shift with elevation! 

As a savvy adventurer some research into the weather conditions of your destination is a must. This will also ensure that you travel light, but are ready for it all. 

Your three main layers will allow you to comfortably and safely go into the mountains with the confidence that you can take any weather you encounter. 

But are all fabrics and layers equal? Nope. Most certainly not, and definitely not in the summer! Be sure to pay attention to the fabrics, weight and quality of your gear.

Here are some things to remember for summer:

  • Weather can change quickly: Be sure to consider the full range of temperatures and weather you may encounter. Conditions can be dramatically different as you go from hiking below tree line to crossing a glacier to reach the summit. Don’t forget your extremities such as hands, head and feet.
  • Weight vs. comfort: You don’t want to weigh down your pack, but you do want to be prepared. These trade offs are crucial. With proper research you can make educated decisions on whether your heavier layers are needed, or if you can keep it light. 
  • Functionality: Outdoor clothing can be loaded with all kinds of features. From pockets, vents and hoods to things like sun protection, insect repellent and antimicrobial treatments to reduce odors – you can find what you need. Try to avoid unnecessary features that only add weight and cost.
  • Fabrics: We don’t like cotton. Cotton takes a very long time to dry and is a poor insulator, so cotton should always be avoided on mountaineering climbs. Choose wool or synthetic options, like polyester or nylon, instead.

Warm-weather base layers: Though long underwear might not be appealing when temperatures soar, having dry skin generally makes you more comfortable in all conditions. Here are some of REI’s other warm-weather base-layer considerations:

  • Any summer shirt is really a base layer, so look for ones that offer wicking.
  • Some shirts designed for warm weather spread the moisture out through the fabric, where evaporation helps with cooling. When looking for these layers, be aware that they won’t really be marketed as a base layer, but as your next-to-skin layer they can increase your comfort in hot conditions.
  • Underwear like briefs, boxers and bras should also wick (the same is true when you wear it under your long underwear in winter).
  • UPF-rated base layers give you added sun protection. Read How to Choose Sun Protection (UPF) Clothing for more details.
  • Cotton, considered a no-no in winter because it sponges up water and can chill you, can be okay if you’re outside on a super-dry, summer day that doesn’t make you sweat – unless you’re okay with sweating through your shirt a bit!
  • Emerging fabric technologies, like wool infused with ceramic particles, will offer base layers that literally cool your skin for greater comfort.

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Layering for Snow 

Low Intensity

Ice fishing, belaying, hunting in a blind, an easy walk around the block – these low intensity activities have their own wardrobe. Here are some ideas!

From left: Kari Traa Lokke Half-Zip Base Layer Top (Women’s), $120; Patagonia Los Gatos Quarter-Zip Fleece Pullover (Women’s), $99; PICTURE ORGANIC CLOTHING Seattle Bib Snow Pants (Women’s), $219; Mountain Hardwear Direct North GORE-TEX WINDSTOPPER Down Jacket (Women’s), $400

Materials

Merino wool has one of the best warmth ranges of any fabric, thanks to the natural crimp (or zigzag) of its fibers. It traps air in tiny pockets, which warms up fast from body heat.

Synthetic fleece is usually made of polyester. It’s highly breathable and dries fast, and because it typically isn’t bulky, you can easily slide it between other layers.

Down is the fluffy stuff between the bird’s body and feathers. It creates tons of pockets of air (an ounce of down can have as many as 2 million filaments). It has the best warmth-to-weight ratio when it’s dry, but it loses loft when wet.

CLICK HERE FOR THE BEST LAYERS FOR WOMEN+!

 

 

Mid-Low Intensity

Resort skiing, building a snowman, a moderately paced walk, snowball fights, slow snowshoe strolls – here are some ideas for those mid to low intensity adventures. 

From left: Smartwool Intraknit Merino 250 Quarter-Zip Base Layer , $150; Arc’teryx Atom LT Insulated Hoodie, $259; Helly Hansen Legendary Insulated Snow Pants, $200; Arc’teryx Beta AR Jacket, $575

Materials

Body-mapped base layers use a construction that places different weights of fabric across the garment. Heavier materials go where you require more insulation, like your torso, while lighter materials go where you sweat, like your back and underarms.

Synthetic insulation is composed of man-made threads that are spun to create pockets of air, mimicking down. It’s not as compressible as down, but it’s warm when wet, dries quickly and is usually less expensive. New from REI Co-op, the Flash Insulated jackets (available in hooded, non-hooded and vest options) fit this mold well.

Waterproof/breathable shells (like GORE-TEX) often use a three-layer sandwich: The interior liner wicks sweat off your skin through a membrane, and the face fabric repels moisture.

 

CLICK HERE FOR THE BEST LAYERS FOR WOMEN+!

 

 

Mid-High Intensity

Snowshoeing, backcountry skiing, fat-biking, ice climbing, an intense snowball fight – here are some ideas for mid to high intensity activity.

From left: REI Co-op Midweight Base Layer Crew Top , $49.95; Norrona Lofoten Alpha 120 Zip Hoodie, $159; Outdoor Research Hemispheres Bib Snow Pants, $599; Dynafit Radical GORE-TEX Jacket, $499.95

Materials

Synthetic base layers are often lighter and more breathable than wool, making them great at wicking sweat from your skin and drying quickly. But they aren’t as resistant to body odor.

Hybrid mid layers take the best of your base and mid layers to create breathable insulation. Typically, down or synthetic insulation is used around your core, while the remaining areas are constructed with thinner, more breathable fabrics.

Performance waterproof/breathable shells let sweat escape and repel moisture. This one uses GORE-TEX C-KNIT, a three-layer sandwich with a more breathable and stretchy internal liner.

CLICK HERE FOR THE BEST LAYERS FOR WOMEN+!

 

 

High Intensity

Running, cross-country skiing, any cardio workout outdoors…. these sweaty moments need something special. 

From left: Patagonia Capilene Midweight Crew Base Layer Top (Women’s), $59; The North Face Winter Warm High-Rise Tights (Women’s), $85; Salomon Agile Wind Print Hoodie (Women’s), $90.

Materials

Nylon is highly abrasion-resistant and strong enough to be worn alone (unlike a base layer). It’s fibers have solid elastic-recovery behavior and wick sweat.

Ultra-breathable synthetics, like Capilene from Patagonia, sacrifice heat retention in the name of breathability, wicking and quick-drying capabilities.

Polyester on its own isn’t waterproof (and barely water-resistant), but it excels at blocking wind while allowing sweat vapor to escape. Plus, it’s light enough for cardio activities.

 

 

Layering for Dry Cool Weather

Cool Weather

Hiking in temperatures between -1C and 10C (30F and 50F)

Featured Products:

Look into a base layer with offset shoulder seams like the 200 Oasis Crew. Such tops have seams that won’t chafe beneath your backpack straps. Combined with merino wool, which is naturally abrasion resistant, this shirt should ensure your comfort on the trail.

Pants with built-in armor like the Abisko Trekking Tights will withstand natural wear and tear longer. These specific tights use aramid, an insanely strong, heat-resistant class of synthetic fibers (commonly referred to under the brand name of Kevlar). Frequently used in body armor and aerospace fabrics, aramid is woven into hiking apparel throughout abrasion-prone areas for protection.

Insulated vests are the do-it-all layer for active warmth. The Flash Insulated Vest uses PrimaLoft Silver Eco insulation made with 70 percent post-consumer recycled content, which surrounds your core where you need warmth the most. The lack of arms prevents overheating when you’re exerting yourself on tough climbs.

Cover it all with a lightweight shell than can easily stow away in your pack like the Westwinds Jacket.

 

Cold Weather

Hiking in subfreezing temperatures.

Featured Products:

Hybrid base layers like the Warm Half-Zip Turtleneck are constructed from a blend of wool and synthetic. This means they grant the odor-resistance and warmth of wool combined with the durability of synthetic fibers for long-haul days on the trail.

Pair a hybrid base layer with boot-length base layer tights like the Merino Mid-Weight Boot-Length Bottoms. They cut off the leg at the shin like capris, which prevents bunching and hot spots around your socks. You still get the warmth and moisture management of a full-length base layer bottom.

Go for a softshell pant like the Chockstone. Softshell fabrics (like the 91 percent nylon/9 percent elastane blend here) maintain a high level of warmth like hardshells but are more breathable. Softshells also allow for a full range of motion while climbing steeps. Note: They’re often heavier than hardshells.

Pack a puffy like the 650 Down Jacket and a shell like the Norvan SL just in case.

 

We hope that this course helps you feel even more confident in your next adventure! If you are going out and about, and this course helped you prepare, we would love to see your adventures! Tag us on social media for reshares, story shares and more!

 

 

 

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