Breathable when it needs to vent, warm when it needs to insulate. This jacket became a second skin for one tester who wore it nonstop for four days of ice climbing in New Hampshire, then around-the-clock on a four-day summer climb of Mt. Rainier. There is no single magic ingredient. It’s the full recipe at work: Polartec Alpha, an insulation with thousands of tiny perforations that allow body heat to escape, is sandwiched between a wicking polyester liner and tough-but-supple nylon shell. “It’s an ideal outer layer when you’re grinding hard uphill in deep cold, and it makes a low-bulk midlayer under a shell,” one tester says.
The hood fits over a climbing helmet, but also adjusts snugly over a beanie. Five pockets (two interior) store winter must-haves. A sturdy, two-way zipper let us vent from top or bottom and access a climbing harness. We liked the clean cuffs (they have Lycra inserts to block wind) which play nicely with other layers and gloves.
You’ll be wearing this jacket way more than packing it, but you can squish it down to about 7 by 5 inches in its own pocket. It’s a bit on the heavy side compared to other midlayers, but that’s a price we’re willing to pay for its versatility.