Baselayers are the staple of any great day on the mountain, maintaining and regulating your core temps as the weather and your pace inevitably shift. This active insulation is the foundation of any layering kit, from dawn patrol in the backcountry to casual days at the resort to fat biking on the local trails or even curling up at home by the fire.

Recognizing that everyone operates differently on the mountain—some running hot, others reaching for thicker insulation— we’ve expanded our existing Basis collection to include a new midweight baselayer that delivers the added versatility you need to layer up properly for the adventures ahead, all winter long.

Introducing our latest in performance insulation: PeakWool Midweight Merino 

To design a midweight layer capable of delivering heavier-duty, dependable warmth with the natural performance benefits of our first-ever 100% merino offering, we partnered with Südwolle in New Zealand, the most trusted source for premium, responsibly and humanely sourced merino wool. Together, we formulated and fabricated a Stio-exclusive performance fabric that answers on all the foundational benefits our midweight baselayer program was intended to achieve:

✓ Thermo-regulating warmth for the coldest ski days

✓ Moisture management to wick sweat and keep you dry

✓ Super soft, buttery handfeel inside and out for silky comfort

✓ Versatility to wear it everywhere—even to bed at night

✓ Reduced pilling and added durability so it lasts season after season

✓ Natural anti-odor so you can wear it for days on your backcountry missions without washing… 

And of course, ensuring it could do all of that sustainably.

Proprietary to Stio, this double-knit, midweight material is made of responsibly and humanely sourced sheep’s wool, blended with Tencel for added softness and a silky smooth hand feel inside and out, recycled nylon for moisture wicking and improved durability, and a touch of spandex for added stretch and comfort.

Using Beta-spun construction to wrap these high-performance, synthetic materials around our naturally high-performing wool, we maximized the performance properties of the final, finished product to deliver a baselayer capable of so much more than traditional merino. The result is an entirely new dimension of satiny softness and stretch comfort you'll want to live in all winter long.

How do the Basis midweight and lightweight compare?

Double the knit, double the weight.

Compared to our lightweight Basis Power Wool™, our PeakWool™ double-knit adds weight and warmth for really cold days on the mountain, and on warmer ones—for those who run hot—it may eliminate the need for a midlayer altogether, reducing bulk and improving mobility.

For those who always run cold, this midweight option provides added insulation when the temps dip below your comfort zone thanks to the natural thermo-regulating qualities of merino construction, which insulates in colder conditions but keeps you cool when the freeze lifts.   

• Midweight Basis PeakWool: 56% Merino Wool, 23% Tencel, 12% Recycled Nylon, 7% Virgin Nylon, 2% Elastane
• Lightweight Basis Power Wool: 69% Polyester, 31% Wool

Our midweight and lightweight options ensure you’re covered at every temperature and for every activity level, however, hot, cold or sweaty you tend to operate, all winter long.

See the Full Baselayer Collection:

• Shop Men's
• Shop Women's