As runners, we rarely shy away from uncomfortable conditions. From high-mountain ridge running to humid summer slogs, we are out there logging miles in all seasons. While we are willing to get out there when the going gets tough, that doesn’t mean we are willing to sacrifice all our comfort.
As the saying goes, “There’s no bad weather, only bad clothing.” One material that can be counted on to keep you comfortable from wet to dry, cold to hot, and everything in between is wool. While wool is often thought of for cold-weather comfort, it is much more versatile than just being used for a cozy sweater.
In this guide, we share our favorite wool items to keep you moving in the best and worst conditions Mother Nature can create.
Why the iRunFar Team Chooses Wool for Running
When we talk about wool for athletic performance clothing, we are talking about merino wool. Merino wool is a fiber grown by merino sheep, which are a rugged breed that evolved to withstand temperature extremes in mountainous terrain. Merino sheep are most commonly raised in Australia and New Zealand, where they can withstand temperatures from five to 90 degrees Fahrenheit with their warm yet lightweight and breathable fleece. This fleece creates a fine, lightweight fiber that is much softer and more breathable than traditional wool — so you won’t feel like you are running around in an itchy turtleneck.
Merino clothing works its magic by trapping air to provide insulation while transporting moisture away from your skin, keeping your body at a stable temperature. Unlike synthetic fibers that wick large moisture droplets away from your body, merino wool is porous and allows moisture vapor from sweat to escape before it turns to liquid droplets, eliminating the wet clammy soaked-in-sweat feeling during and after a run.
In addition to its temperature- and moisture-regulating capabilities, merino wool also has several other features that make it a top choice among performance fabrics. Merino wool is inherently odor-resistant, making it a perfect choice for multiday adventures, fastpacking, travel, or just skipping a laundry day here and there. It is a great layering material as well, with many companies making layers of varying weights to accommodate a range of temperature conditions.
Clothing items geared toward warm weather activities will generally be made of a blend of merino with another material, such as Tencel, nylon, or polyester, to make them lighter and quicker drying. Warmer insulating items will more often be 100% wool — or close to it — to increase heat retention.
Merino wool is an environmentally friendly material that is biodegradable. All the companies featured in this guide source their wool from humanely raised, ethically sourced, non-mulesed sheep — so you can feel comfortable about investing in products that are good for the environment, good for the animals, and good for you!
Best Lightweight Long-Sleeve Shirt: Smartwool Classic All-Season Merino Base Layer Long Sleeve ($85-$90)
Formerly called the Merino 150 Base Layer, the Smartwool Classic All-Season Merino Base Layer is a versatile layer that many on the iRunFar team have been using for years. This lightweight long-sleeve shirt works great as a standalone shirt, over a short-sleeve shirt for added warmth, or as a layering piece on cold days. The material is 87% merino wool fiber that is wrapped around a nylon core to increase durability while maintaining the wool’s softness as well as its temperature- and moisture-regulating properties.
This top is available as a crew neck and quarter-zip, the latter of which was a top pick in our best cold weather running gear guide. I loved mine so much that I loaded my closet up with several in multiple colors, and it has become a favorite top for chilly runs, casual wear, and travel. I find it performs exceptionally well on cold and wet days as a layer under a vest or rain jacket to maintain dryness and warmth without overheating. It has also remained stink-free on some long running and hiking days.
Check out our in-depth Smartwool Classic All-Season Merino Base Layer Long Sleeve review.
Best Midlayer Long-Sleeve Shirt: Smartwool Classic Thermal Merino Base Layer ($110)
The Smartwool Classic Thermal Merino Base Layer, formerly called the Merino 250 Base Layer, is a 100% merino wool long-sleeve shirt designed to keep you toasty warm in cold conditions. Available in a crew neck and quarter-zip, this thermal merino base layer is designed for a slim fit for next-to-body warmth and ease of movement. Added shoulder panels and flatlock seams help prevent chafing and pressure points.
This layer is thick and provides some serious warmth — something to keep in mind if you tend to run hot. For those of us who need the added warmth, this is a versatile piece that can be worn as an outer layer on its own or under a jacket or shell in wet or snowy weather. This base layer is also great as a travel or camping shirt in chilly weather as it is nice and soft and resists odor, though we recommend sizing up for more casual wear.
Best Short-Sleeve Shirt: Black Diamond Rhythm T-Shirt ($75)
The Black Diamond Rhythm T-Shirt is an iRunFar favorite that has earned high marks for its performance on both warm and cool running days. The shirt is made from 57% nylon and 43% merino wool, making it an extremely lightweight, breathable, and quick-drying shirt that resists odor and maintains its stretch and shape even after several days of use. From casual wear to long travel days, and from short runs to multiday adventures, the Black Diamond Rhythm Tee is the short-sleeve shirt we reach for time and time again.
This shirt has been previously reviewed in our Black Diamond apparel review and our in-depth Black Diamond Rhythm T-Shirt review. It was named the best for unpredictable weather in our best running shirts for women guide. Perhaps iRunFar founder Bryon Powell put it best when describing this shirt: “When the biggest ding on a running shirt is that I too often find myself pulling it out to wear casually, you know you have a winner.”
Best Shorts: Smartwool Merino Sport Lined Short ($60)
Ok, so shorts are probably not the first item of clothing anyone thinks of when talking about wool, but there are some great ones out there to choose from. The key for wool clothing is that the wool is next to skin; for running shorts this means the wool material is most often in the liner.
Our top pick is the Smartwool Merino Sport Lined Short, which features a merino wool-blend liner for breathable, quick-drying comfort. The outer shell is a stretch-woven blend of recycled polyester for freedom of movement without bulk and is available in both neutral colors as well as some fun patterns for a little pizzazz. The men’s version comes in a five- and eight-inch inseam, while the women’s version is a three-inch inseam.
These shorts were a pick in our best running shorts for women guide, where our testers loved its modest cut and wide, comfortable waistband. Two small pockets add a little storage for small items like a key or gels. These shorts are great for trail runs, hikes, or paddleboarding — whatever warm weather adventures you choose!
Best Sports Bra: Smartwool Merino Sport Seamless Racerback Bra ($60)
The Smartwool Merino Sport Seamless Racerback Bra is a top choice for many iRunFar team members for its simple design, soft itch-free fabric, and long-wearing comfort. While it performs well in both hot and cool weather, it really shines in cold-weather pursuits and was named the best for cold weather in our best sports bras for running guide.
The Smartwool Merino Sport Seamless Racerback Bra features a stretch-nylon shell for compression and support with a 70% merino wool-blend liner for seamless, temperature- and moisture-regulating next-to-skin comfort. This bra’s odor-resistance and seamless design make it one we continuously reach for, especially on long or multi-day outings. Its one drawback is a lack of support for larger chests — it is still super comfortable and a great pick for travel and hiking but not the best for high-impact activities like running.Shop the Smartwool Merino Sport Seamless Racerback Bra
Best Sports Bra: Ibex Balance Crop Bra ($70)
The Ibex Balance Crop Bra is part sports bra, part crop top, and all comfort. With a longer profile than a standard sports bra, this merino wool-blend crop has some stylish features that make it a great standalone top in warmer temperatures. The Ibex Balance Crop Bra has more support for larger cup sizes than the Smartwool Merino Sport Seamless Racerback Bra reviewed above, making it a great choice for larger-chested runners who want to take advantage of the comforts of merino wool.
This bra is a little on the pricey side, but the temperature- and odor-controlling features mean this bra can be worn multiple times before needing a wash — making it perfect for travel and long adventures in the mountains.
For more options, check out our guide to the best sports bras for running.Shop the Ibex Balance Crop Bra
The Darn Tough Stride Micro Crew Ultralightweight Sock is a fan favorite due to its low-bulk seamless fit. The merino wool blend keeps feet dry, comfortable, and blister-free mile after mile, and light arch support eliminates bunching and shifting as you move. These running socks are reinforced at the heel and on the sides to improve durability for long-lasting comfort. A six-inch cuff provides ankle protection against trailside sticks and debris.
Darn Tough is a family-owned company you can feel good about shopping with. Their merino wool is 100% Responsible Wool Standard certified, and all Darn Tough socks are made in the USA in their mill in Vermont. If any durability problems do arise, Darn Tough socks are guaranteed for life — simply return the socks in question and they will replace them under warranty.
For some of our favorite running socks, check out our best running socks article.
Best Socks: Smartwool Athlete Edition Run Crew Socks ($26)
The Smartwool Athlete Edition Run Crew Socks are lightly cushioned merino wool-blend socks that really stand up to the distances and terrain trail runners subject them to. The design combines areas of extra durability and cushion with mesh zones to enhance breathability, keeping feet dry and happy. The higher crew-length cuff protects ankles and lower legs from sticks, rocks, and other trail debris that would otherwise leave us scraped and scratched.
They were featured as the runner-up in our best running socks guide, and our team found them to perform well in a variety of weather and terrain conditions. As one tester put it, their feet felt “cradled and comfortable” by the Smartwool Athlete Edition Run Crew Socks. As if superior fit and comfort aren’t enough, these socks come in some fun colors and designs to jazz up your running ensemble.
Best Neck Gaiter: Buff Merino Lightweight Neckwear ($29)
The name Buff has become nearly synonymous with neck gaiters, so it’s no surprise our favorite neck gaiter is from the company that has kept many a runner’s neck warm for years. The Buff Merino Lightweight Neckwear is soft, wind resistant, semi-seamless, and made of 100% merino wool.
This light yet toasty layer is breathable and dries quickly, using wool’s ability to maintain warmth and help with temperature regulation even when damp. Buff’s multifunctional design means you have the option of using it as a hat, headband, neck gaiter, ear warmer, or face cover, all in one lightweight tubular package.Shop the Buff Merino Lightweight Neckwear
Best Gloves: REI Co-op Polartec Power Wool Gloves 2.0 ($50)
The REI Co-op Polartec Power Wool Gloves 2.0 are a lightweight merino wool, nylon, and spandex blend that members of our team found to be durable and comfortable. Though they are relatively light, they were noted to provide excellent warmth for their weight. They are a versatile investment and work great as a standalone glove or layered under a heavier or waterproof mitt for extra warmth and protection.Shop the REI Co-op Polartec Power Wool Gloves 2.0
Best Beanie: Smartwool Active Beanie ($25)
The Smartwool Active Beanie, formerly known as the Merino Sport 150 Beanie, is a sleek, lightweight beanie that provides a little extra warmth and protection on chilly runs without being itchy or bulky. The beanie’s combination of merino wool and polyester provides the temperature and moisture management of wool with some stretch and fast drying times.
This low-profile beanie is slim enough to layer under a helmet and is easily small enough to tuck into a pack or pocket for those just-in-case moments or when your head heats up and needs a break. The Smartwool Active Beanie was a top pick in our our best cold weather running gear guide as well.Shop the Smartwool Active Beanie
Best Hat: Buff Pack Merino Fleece Cap ($39)
If you are looking for visor protection, lightweight warmth, and a built-in ear band, the Buff Pack Merino Fleece Cap is for you! Another pick in our best cold weather running gear guide, this hat has a unique design that checks a lot of boxes for cold weather running. Say goodbye to an ear band or beanie piled on top of your brimmed hat — this hat does it all and stuffs away in your pocket when you don’t need it.
This lightweight, packable running hat has a baseball hat-style brim with a merino wool cap to combine face and eye protection from the sun with breathable warmth. The ear band can be pulled down for added warmth and coverage in colder conditions.Shop the Buff Pack Merino Fleece Cap
Call for Comments
- Do you run in wool clothing? Which items or brands are your favorites?
- In what weather or temperatures do you find wool to be the most comfortable?