Leave the Patagonia Nano-Air Light Men's Jacket on from the trailhead to the summit and it will keep up the whole way. This active-insulated midlayer breathes like a fleece but warms like a puffy, thanks to a stretchy fill that lets air pass right through.

Why we like it:

What makes it special is how it sheds excess heat during hard work, so you are not constantly stopping to vent or peel a layer.

Features and Functions:

The jacket uses 40 gram FullRange insulation, an air-permeable stretch synthetic that regulates temperature on the fly, housed in a stretch-woven recycled shell treated with durable water repellent. Zippered handwarmer pockets hold small essentials, elasticized cuffs and hem trap warmth, and the jacket is stitched at a Fair Trade Certified facility.

Fit and Sizing:

It has an athletic, stretch-friendly cut built to move, with sizing that hits true over a baselayer.

Bottom Line:

This is the layer for aerobic, variable-effort days, from skinning uphill to cold resort skiing where you rarely stand still. Best for skiers who run hot and move constantly.