Our gear editor wore this shirt for more than 20 days of hiking, skiing, and hut lounging. She says the midweight fabric is warm enough for high-exertion outings on sub-zero days, yet not heavy enough to cause overheating in temps up to 30°F.
"Skinning up Mt. Mansfield with a light jacket on top, I was sweating but I never felt wet, even when I reached the top and started to cool down," she says. It has all the merino attributes we love–soft, stretchy, and naturally anti-stink. $85; 8 oz. (w's M); men's S-XXL, women's XS-XL; smartwool.com.