What We're Testing Now: Four Winter Layers for Guaranteed Warmth

Winter insulation is a broad gear category here at Backpacker, stretching from lightweight, breathable fleeces for high-tempo ski tours to heat-hoarding parkas capable of keeping you warm on sub-zero camping trips. I’ve had the chance to try a little bit of everything this winter in my capacity as testing category manager, mixing and matching different pieces to put together my favorite insulation kits. We’ll have a thorough look at that ideal layering system in the Winter Buyers’ Guide due out this coming fall, but here’s a sneak peak at some of the upcoming products I’ve had the chance to take out into the cold.

Rab Mythic Ultra

This puffy is one of the most-hyped insulated pieces debuting next fall, and for good reason. It packs undeniable warmth into an impressively small and lightweight package, slipping a generous amount of 900-fill down behind minimalist Pertex Quantum fabric. The jacket employs a reflective internal scrim with the down to bounce your body’s heat back to you without adding much weight or bulk. The result: My sample packs down to barely larger than a 32-ounce Nalgene and has kept me warm down to nearly 0°F. What remains to be seen, though, is how durable the 10-denier ripstop holding it all together is, and only a full season of testing will tell us for sure. 

The Pak-Jak

The Pak-Jak is unquestionably the most unique and functionally innovative jacket in this year’s insulation testing lineup. The problem its creators set out to solve is the difficulty of repeatedly taking your puffy off and putting it back on while you’re wearing a backpack. With all other jackets, you can’t, but the Pak-Jak has a giant removable zippered panel from neck to hem on your back. For me, its usefulness seems limited: I run warm and almost never shoulder my backpack while I’m wearing a puffy. But for someone who runs cold and finds themselves shuffling around their layers a lot, it might work pretty well. You can even replace the back panel with a mesh one, if you don’t want insulation between you and your pack. Ding: All those zippers definitely add weight.

Montane Fireball Lite

For an unusually warm Colorado winter, the Fireball has quickly become my favorite lightly-insulated midlayer for ski touring. The jacket mixes synthetic Polartec Active Eco insulation in the chest, back, upper arms, and hood with a thin, stretch grid fleece under the arms and on the sides to fill what, at least for me, has been the predominant temperature hole of the season: I like it a lot for ski tours in the mid-20s to mid-30s, when I want a little more insulation than a fleece, but not as much as a heavier jacket. Montane covered Fireball Lite in a stretchy, air-permeable face material that’s kept me from ever feeling too clammy in the jacket, even when the sun comes out. 

Mountain Hardwear Polartec Power Grid Full Zip Hoody

On the outside, this Mountain Hardwear fleece looks like your prototypical technical grid fleece, a la the Patagonia R1. But after a season of testing, I’ve probably pulled the Mountain Hardwear out of my closet more often than my R1, thanks to some small upgrades. It has both chest and hand pockets, a slightly more relaxed and comfortable fit, and stretchy cuffs (with thumb loops) that make taking gloves on and off a cinch. I’m also a big fan of the hood, which somehow fits comfortably over just a baseball cap, but stretches to accommodate a helmet without making me feel like my neck is being compressed into my body.