It’s late summer, the hottest days of the year, and I’m wearing a lot of wool clothing. In fact, I’d argue it’s the best T-shirt material for warm weather you could buy.
Recently, I realized much of my favorite summer clothing from the past 2 years is made by wool brands. This isn’t your usual “wool is magic” hype. These boxers, shirts, and sun hoodies use a hybrid design, mixing wool with other materials for more performance benefits and fewer drawbacks.
I test all kinds of apparel, but the ones I reach for first on runs, hikes, and on trips now tend to be some sort of wool blend. I first fell in love with the idea of a summer wool running shirt thanks to the (now-defunct) Black Diamond Rhythm Tee, a lightweight top that incorporated stretchy NuYarn wool. Since that time, other wool shirts have gained traction in my summer wardrobe.
If your summer go-tos don’t include some wool, I think you’re missing out.
I contacted three brands known for making wool garments to find out what changes in designs (and perception) are behind the transformation of my summer gear closet. What I discovered were new yarn technologies and an overall improvement in wool apparel from just a few years ago.
You’ll see that while Smartwool, Ibex, and PAKA share a woolly reputation, each brand takes its own approach to creating more summer-friendly wool clothing. Don’t worry; I won’t go too deep into the tech weeds.
Wool Blends: Why They Matter
Wool is known for its ability to regulate body temperature, wick sweat, and ward off odor-causing bacteria. That’s why it’s so popular in base layers, where many people first encounter the fabric. Because of that, many people tend to only associate wool with winter and cold-weather activities — but that’s a misunderstanding. Wool blends (like merino) are great year-round.
One of the biggest downsides to summer-weight wool garments, though, is that they tend to be fragile. A purely wool shirt can pick up holes from backpack strap abrasions, getting snagged on something, or just being looked at wrong.
That’s why wool brands have been incorporating nylon and even spinning wool around nylon. This gives wool a stronger, structural backbone that is less prone to sagging and stretching. Blending synthetics into wool helps the garment wick sweat even better, keeping you drier than a cotton T-shirt would.
By embracing these hybrid designs and incorporating new yarn technologies, wool brands are finding sweet spots for summer performance clothing.
Tencel & Summer-Weight Wool Clothing
One ingredient I’ve seen popping up in summer apparel is Tencel, a brand-name lyocell fabric mostly derived from eucalyptus pulp and produced in a closed-loop process where the solvents are recycled and reused. It’s also biodegradable. Tencel had a moment roughly 5 years ago, dipped out, and has returned.
According to Andrew Slaybaugh, a senior product line manager at Smartwool, this combination helps create an exceptionally breathable fabric, which is great for high-aerobic activities in warmer weather.
“I believe this resurgence of wool-Tencel blends is due to brands trying to make a shift toward sustainable, high-performance apparel,” Slaybaugh said. “We know merino wool supports natural temperature regulation, moisture-wicking capabilities, and odor resistance, while Tencel contributes exceptional softness, breathability, and efficient moisture management, ensuring a cool and dry experience during workouts.”
Another reason Tencel is becoming popular in wool blends is cost. Tencel is cheaper than wool, so incorporating more of it helps the bottom line in a market where new costs keep arising.
A Shining Example
I have run in Smartwool’s Active Mesh Short Sleeve all summer, and have enjoyed how well it wicks sweat on the move and dries out once my sweat inevitably pools. This shirt was one of the first pieces that made me stop and evaluate what it was made from. It’s a perfect example of a design callout working, as it has different mesh textures that can be seen and felt.
“Our Active Mesh collection combines the natural benefits of merino with the quick-dry time of recycled polyester, and cooling properties of Tencel Lyocell fiber,” Slaybaugh said.
The Active Mesh Short Sleeve is body-mapped with a mix of merino wool and Tencel in the front of the shirt and a (near equal) mix of wool, lyocell, and polyester used for mesh ventilation in the shirt’s back, sleeves, and shoulders. This blend is used in much of Smartwool’s Active Mesh collection of tops and active short linings, and the brand uses terms like “Ultralite” and “All-Season” to convey the summer use of such garments.
In my experience, this shirt is great for runs and hot hikes. It helps that it gets several uses between washes and has held up admirably to months of shorter runs.
P.S.: I also swear by wool linings in shorts.
Incorporating Synthetics
I will admit that the humidity here in Colorado is not the same as the humidity in the southeast, where I grew up. However, I will now sweat at the first hint of humidity. All summer, even on East Coast trips, I’ve packed wool shirts to help me stay dry.
Ibex makes two of my favorites for semi-active daily wear, travel, and hikes. There’s the GOAT and Paradox tees. Both are about as light as you want to get with wool before you run into durability issues.
Looking into the differences of these two shirts, I once again came across the use of Tencel and a new yarn technology that’s been off my radar. So, I reached out to Ibex general manager Jordan Todoroff to learn more.
“From a performance perspective, the hardest part is selecting and creating fabrics that can be lightweight enough to wick moisture, dry quickly, and keep the end user cool while still maintaining durability and sufficient sun protection,” Todoroff said. “To boost durability, we’re using core-spun yarn, new Beta Spun yarn technology, and Tencel blends.”
For its Paradox material, Ibex blends merino wool, Tencel, and nylon. But it’s not just a blend, it’s how it’s blended. In this case, the Corespun technology wraps the wool and Tencel fibers around a nylon filament. This adds strength to the fabric while keeping the performance of wool and Tencel against the skin, where it can wick and cool during hot and humid weather.
Is It Cooler?
In my experience, the inclusion of Tencel makes the Ibex Paradox Tee feel cooler. Even out on mesas with nowhere to hide from the sun, and my exposed skin asking for relief, the Paradox Short Sleeve feels cool. That’s hard to measure in the field, but it’s not just cool for wool. It’s cooler than other synthetic shirts, which can feel hot to the touch after prolonged time in the sun.
I still come back from runs and hikes with patches of sweat, but they dry fast. Most noticeably, this shirt doesn’t seem to pool sweat behind a backpack during hikes as much as other shirts I own.
Ibex’s Paradox technology extends into the brand’s Enduro Collection. I haven’t tested it, but it’s worth a mention. According to Todoroff, the Enduro Collection is a summertime riff on the brand’s all-wool Shak Collection.
“We combined the Shak’s double knit structure with our Paradox technology to make the fabric 40% cooler in the heat to make this perform as well in the summer as it does in the winter,” he said. “The resulting [Paradox Ponti] makes an absolutely bomber short and leggings.”
A New Tech
I really like the Ibex GOAT Shirt for its loose fit and offset shoulder seams. It’s also generally just comfortable in hot weather. But it turns out the shirt is a prime example of new-to-me Beta Spun yarn technology!
Beta Spun technology wraps ultrafine merino wool inside a nylon sheath. It creates a light material with the more durable nylon on the outside while still benefiting from wool’s wicking and odor-fighting properties. In essence, it’s the opposite of Corespun.
Ibex dubs the resulting material “Weightless Wool.” It is indeed very lightweight, yet still provides UPF 50+ sun protection.
Even Cotton Has a Place
For more day-to-day versatility and less performance-based needs, look no further than PAKA’s Ultralight Coolplus sweater. It’s an ideal layer at elevation or in cooler environments.
PAKA’s design director, Megan Krajco, explains how a blend gets the performance perks of alpaca into a summer-weight piece.
“By using a yarn that blends Alpaca with organic cotton and Coolplus viscose, we were able to achieve the perfect warm weather blend of comfort and performance,” Krajco said. “Coolplus technology uses viscose fiber in a unique spinning process, which creates a larger fiber surface in the cross-sections of spinning. This allows moisture to evaporate more quickly without added chemicals or synthetics.”
Well before its work with Coolplus tech, PAKA has been making my favorite summer base layer — aka underwear. I’ve worn PAKA Essentials boxer briefs for a while now. They are my go-to choice for backpacking trips and travel.
Summer Base Layer
The brand recently added more styles of briefs and boxers as part of its updated PAKA Essentials 2.0 collection. The men’s and women’s underwear uses PAKA’s proprietary tri-blend of Tencel, organic Pima cotton, and royal alpaca wool with a touch of spandex for stretch throughout. The result is comfortable and quick-drying underwear. It’s great for low-cardio activities, travel, and everyday comfort in all temperatures.
Reconsider Wool Clothing for Summer
If you’ve shied away from wearing wool clothing in the summer, consider this a challenge to shake things up.
If you’ve worn wool before and found fault in its wicking or durability during prolonged efforts, try one of the more performance-oriented blends like the Smartwool Active Mesh or Ibex Paradox short-sleeve shirts.
These newer, hybrid pieces really do outperform similar options from just 5 years ago. And they should hold up much longer, too, even if they get a hole or two. At worst, it could become a workout shirt.
I’ll fully acknowledge that wool blends aren’t the cheapest options. However, if you can get past any price comparisons with purely synthetic goods, there’s a worthwhile difference in quality (and sustainability).
Lastly, while I didn’t get into the differences of wools, the feel of alpaca and cotton against the skin is amazing. Anyone who has found merino wool to be scratchy should give those other types of wool a try. You’ll find plenty of praise for alpaca wool’s comfort and performance at GearJunkie. The PAKA boxers are a good entry point to the brand’s apparel.
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