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Why Wool Makes The Best Hiking Sweater

How to layer for the trail, built around one wool sweater.


By Lia Klinchik

Wool is the best thing to hike in because it keeps insulating once it is damp, so the sweat you build going up does not turn cold when you stop. Cotton soaks and stays soaked, and polyester holds odor after a single day of sweat.

I like to spend my weekends doing some sort of activity outside, whether that be hitting a farmer’s market, going out to the mountains to hike with my dog, or foraging in the forest.

Because of this wide range of activities, I need clothing that’s adaptable.

Although, throughout time, I’ve ended up with a bunch of low-quality pieces that don’t fit my agenda and have accumulated in my closet.

This happened partially because I didn’t know what I should be buying.

I didn’t think it mattered where my clothing came from or what materials they were made out of. I had to learn along the way.

Durability, warmth, and lightweight fabrics are some of the things I look for when making these purchases now.

I want to stay cool in warmer weather, be comfortable when it gets chilly, and not have to wear a hundred layers.

The key pieces in my outdoor wardrobe are what have kept me safe and warm thru-hiking the Tour du Mont Blanc.

My puffy coat has made it possible for me to summit Mount Washington in its ever-changing conditions.

And the Oliver Charles yak wool sweater is what kept me protected and comfy through temperature drops at night in the snowcapped forests of Idyllwild, California.

Clothing is what keeps us going on our path and all the roads in between.

Whether you’re a well-seasoned traveler or someone who’s just stepping into the outdoor world, it can be confusing figuring out what to buy or what you need.

You want something you can be active in, but also keep cozy in at the end of a long day!

Let’s dive into the core items I always pack when traveling to meet my adventure needs.

Hiking kit laid out on a rug: boots, a teal shell, an orange puffy, a folded grey sweater, a sleeping bag and gas canisters

What Makes A Good Hiking Sweater?

Four things: warmth for its weight, breathability, odor resistance and durability.

You want staples that are, first of all, functional. Style is just a plus. The kind of wool that the Oliver Charles sweater uses, khullu, embodies most of these qualities, making it a perfect base layer or mid-layer.

Khullu is soft, comfortable, and insulating. It’s also odor-resistant, breathable, and quite durable, which checks the boxes for what we look for.

Durability: If you’re going to spend money on an outdoor wardrobe, you want it to last a long time.

Why purchase clothing that’s just going to fall apart?

For sports that are harsher on clothing, like rock climbing, this is more of an issue because your clothing is rubbing up against the rock, which makes more of an opportunity for it to rip.

This is why pants made specifically for rock climbing are often tougher to withstand the abrasion from rocks.

When it comes to durability, wool naturally expands and contracts depending on the environment, meaning it’s flexible. It can bend without breaking or ripping.

The sweater is also 3D-knit, meaning the sweater is seamless, which makes it surprisingly tear-resistant. There are no seams that can unravel.

A hiker seen from behind walking up a snow-covered trail between pines, poles in hand and a pack on

Why Is Wool Better Than Synthetic Or Cotton For Hiking?

Thermoregulation: IMO the most important quality of clothing. When it comes to hiking, and hiking in the winter specifically, you want to stay as dry as possible.

When you’re moving with heavy clothing on, you tend to sweat more. Then, when you stop moving in colder weather, your sweat turns ice cold and you get really cold!

Trust me, it’s not fun. You want to keep this from happening to the best of your ability.

Materials that regulate your body temperature, like yak wool, help prevent you from sweating too much. Or, even if you do sweat a bunch, high-quality wools absorb and release excess moisture and keep you feeling dry.

Always keep in mind whether your clothing is waterproof or windproof. Also, ask yourself: is it breathable, and is it insulated?

Wool regulates body temperature and collects water.

This means wool is moisture-wicking, another important quality of outdoor clothing.

Cotton just doesn’t cut it because your shirt will get soaked within the first hour of your hike. You will then spend the rest of the duration of your excursion wet because it doesn’t dry quickly either.

I’ve seen a massive difference personally between wearing a cotton shirt vs. a wool shirt on a hike. Wool shirts leave you dry, which also means you can avoid carrying an extra shirt to sleep in at night.

I wore my Oliver Charles sweater over my base layers hiking up to Suicide Rock. I didn’t need to wear my puffy coat, as it kept me comfortably warm the way up.

It also was breathable enough so that I wasn’t overheating. While I did sweat, when I got to the top, I dried off quickly and my sweater was never wet!

A woman in a white beanie and dark sweater sitting on a granite boulder, scrub and pines around her
A woman sitting on a granite slab at the summit with her face to the sun, forested ridges behind her

Does A Wool Sweater Smell After Days On The Trail?

No. Wool traps the bacteria that cause odor inside the fiber, so it stays fresh long after a synthetic would need a wash.

This is more of just a plus. Usually, clothing made out of wool helps resist odors, which is great.

If you’re a thru-hiker, this might be something you want to look into. Wool is antimicrobial.

I discovered that wool actively binds and isolates bacteria within its fibers. This isolation of bacteria reduces odor to the point where unwashed wool has 66% less odor intensity than plastic-based fibers.

After all, what causes odor is bacteria hanging around on the skin and in clothes.

In this sense, the Oliver Charles crew neck sweater performed better outside than any of the sweaters I own.

It’s incredibly odor-resistant even after many uses without a wash in between!

Is A Wool Sweater Comfortable To Hike In?

Yes, when it is fine and light. Khullu is as fine as Grade A cashmere, so it does not itch under a pack strap, and a thin knit moves with you.

This is so, so important. I can’t stress it enough because if you’re going to be wearing it all day, you want to feel good. You don’t want to be itchy or feel constricted, etc.

Other things you can think about when making a purchase are if the clothing is lightweight (which will help you move around easier, be lighter on your back, and be more comfortable when layering) and high performance.

A woman sitting in the open tailgate of a car at sunrise, the sun flaring low over the hills behind her

What Do You Wear Under A Hiking Sweater?

Base Layers: Having a set of base layers is helpful to 1) keep you insulated and 2) wick away moisture.

I was taught to always carry my base layers with me regardless of the hike (just in case, ya know).

In the wintertime, I wear my base layers underneath my hiking pants and sweater.

I usually sleep in my base layer set as well when I’m on an overnight adventure. You want base layers to fit well and be close to your body.

They shouldn’t be baggy. Wool is what the outdoor community favors for base layers because it’s moisture-wicking, warm, light, odor-resistant, and comfortable.

Yak wool is also favorable here. I usually sleep in my base layers when I’m camping, but I like throwing on the Oliver Charles sweater in addition to that.

Sweater: A thin, light sweater that is breathable and warm, like the Oliver Charles sweater, is an ideal mid-layer.

Because it’s thin and warm, it can also work as a base.

Thermoregulation is the most important consideration with a base or mid-layer because if you’re hiking in the winter you can avoid wearing a jacket over it. A sweater can keep you insulated, without overheating.

A woman standing on a snow-patched boulder with her arms spread wide against a clear blue sky
A dirt trail running along a ridge at dusk, an orange horizon over distant hills

What Do You Layer Over It?

Puffy Coat: I take my puffy coat with me on every outdoor adventure. I have a down coat from Arc’teryx.

There is a continuous argument about whether to choose a synthetic puffy coat or down.

Synthetic is obviously cheaper but can be heavier and last a shorter length of time.

Down can last a very long time, if it’s well taken care of, but is more expensive. Down puffy coats are lighter and have an equal amount of warmth to the synthetic coats.

They also pack smaller because they compress better. The only words of caution I have with a down puffy coat: don’t wear it climbing.

Windbreaker or Rain Coat: It’s nice to have a jacket that doubles as both. I have a rain jacket from Outdoor Research that doubles as a windbreaker.

For something a little more heavy-duty, I have a shell from Arc’teryx. I wear it in alpine conditions. It’s light, strong, and keeps me protected and dry.

I’ve also worn it in 70 mph winds on the top of Mount Madison in New Hampshire, and it kept me insulated.

Even though it’s a base or mid-layer, I’ve noticed that my Oliver Charles sweater is remarkably good at protecting against wind.

Can One Sweater Cover Hiking And Everyday Wear?

Yes. The same fine knit that is warm enough for the trail is smart enough for the office, so one sweater can do both jobs.

The clothing market is saturated, and there’s a lot of junk out there!

The best way to design your wardrobe for outdoor adventures will always be to evaluate your needs and build around your core pieces.

Think: what kind of activities will you be doing? What season will you be outside in? You don’t have to have the fanciest clothes to head outdoors.

Over a weekend in Idyllwild, I added the Oliver Charles sweater to my basic wardrobe and tested its versatility.

I was curious to see if this “go-to” sweater held up to its reputation, as I’m sure you’re probably wondering too.

It almost seems too good to be true. We see real sustainability problems with a lot of outdoor products, especially those that come from animals and provide supreme warmth.

It seems as though khullu helps eliminate this issue and is also high-performing.

Having guidance and asking questions makes finding the essential pieces to your wardrobe easy.

Think of it as something you only need to do once because these pieces can be shared from adventure to adventure.

After experimenting with the Oliver Charles sweater in Idyllwild, I think that whether you’re an avid adventurer or just like to spend time in nature, it’s a staple you’ll hold on to for life.

After all, these sweaters were designed specifically for those of us who are on the go during the workweek and like to spend our weekends adventuring.

Which Of Our Sweaters Would You Hike In?

Our All-Season Sweaters. They are knit light enough to keep on while you are moving and warm enough to stop in, which is the whole job of a mid-layer. The Crew Neck and the Quarter Zip are both in that line, and both are machine washable.

Our Winter Sweaters are warmer and heavier, so they are better suited to camp and cold-weather days. They are hand wash. For more on the fiber itself, the yak wool guide covers it in depth.

Warm For Its Weight

40% warmer than sheep’s wool, so you carry less.

Works Damp

Holds its warmth when sweaty. A rest stop never leaves you shivering.

Breathable

Lets heat escape as you climb, which keeps sweat from building up under your pack.

Odor-Resistant

Stays fresh for days on the trail. One sweater covers a long weekend.

Mid-Layer

Thin enough to sit between a base layer and a shell.

Seamless

3D-knit with no seams, so there is nothing to give out first.

Yak Wool Hiking Sweater FAQ

What Kind Of Sweater Is Good For A Hike?

A thin wool one: fine enough to leave on from the trailhead to the summit, and slim enough to fit under a shell when the weather turns.

Is Yak Wool Good For Hiking?

Yes, and the reason is what the animal needs it for. Khullu is the down a yak grows to survive a Himalayan winter, so it is warm for its weight and it breathes.

How Many Days Can You Hike In The Same Wool Sweater?

Several days. Hang it up to air overnight, and it is ready for the next morning’s hike.

Do You Wear Anything Under A Hiking Sweater?

Yes, a base layer that fits close to the body. It insulates and it moves sweat off the skin to the next layer out. Over it goes the sweater, and in milder weather the sweater can be the base layer itself.

Is A Wool Sweater Warm Enough Without A Jacket?

Yes, on most days, and that is the point of carrying one. On the way up Suicide Rock the sweater was enough over base layers without the puffy coat coming out of the pack, and it still breathed well enough not to overheat on the climb.

Every good wardrobe starts with owning less and owning better.

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