November 2026: After testing 63 midlayers while hiking, skiing, fat-biking and climbing in wintry weather, we named the Arc’teryx Atom Hoody our Best Overall pick for its do-it-all balance of warmth, breathability, and weather protection. The most durable option is Mountain Hardwear’s Kor Alloy Jacket. The best for ultra-cold conditions is the Marmot WarmCube Active Novus Hoody.
Midlayers have an outrageously demanding job description. Unlike the super-puffy parkas and belay jackets that we wear to stay warm while hunkering down, midlayers provide insulation during activity—a role that calls for a true multi-tasker. Its duties include keeping us warm while venting excess heat, whisking away sweat, and shielding us from the elements.
It’s a tall order, yet our testing team found six insulated midlayer jackets that check all the boxes. These breathable insulators successfully regulated testers’ temperatures while they skied, hiked, biked, and ran in winter weather conditions. Testers typically sandwiched these jackets between a base layer and a waterproof shell.
On climbs, or in dry weather when they ditched the shell, testers also evaluated these toppers for their ability to shed precipitation and buffer gusts. Sizes: XS-XXXL (men’s), XXS-XXL (women’s) Weight: 12.5 oz. (men’s), 11.3 oz. (women’s) Pros and Cons + Balanced performance + Extended sizes + Lots of pockets – Lacks abrasion resistance The Atom has been one of our favorite midlayers since its debut in 2009, and its design has hardly changed over the years except for sustainability upgrades. With stretchy fleece side and underarm panels bridging generous helpings of synthetic insulation in the torso, hood, and arms, it strikes the ideal balance of warmth and breathability for cold weather conditions.
We found the Atom’s insulated panels—packed with 60 grams of polyester loft—plenty warm down to the teens without an outer layer while skinning and bootpacking in the Tetons. One tester, who wore his hoody ice climbing in Silverton, Colorado, called the Atom’s mix of insulation and breathable fleece “perfectly balanced.” The unconfining cut fits most bodies, small or large, and two hand pockets and one internal chest pocket secure valuables. The cinchable hood is big enough for a helmet, which came in handy when temps plummeted during one Idaho-based tester’s fat-bike ride in the Tetons.
The fabric’s fluorocarbon-free DWR finish repelled drizzle during late-November training runs. But the Atom delivers too much insulation for mild conditions and shoulder seasons (at 35 degrees and above, consider the Atom SL.) And although the breathable fabric feels soft next to skin, it gets pilly after repeated encounters with pack straps and other abrasive tools. Sizes: S-XL (men’s), XS-XL (women’s) Weight: 18 oz. (men’s), 15.6 oz. (women’s) Pros and Cons + Attractive patterning + Warm – Large packed size Proving that midlayers don’t have to be thick and bulky to provide significant warmth, this Merino-stuffed puffy goes relatively light on the filling (80-percent wool with biodegradable, bio-based polyester).
Extract — continue reading at the source.
