How do you find top-performing apparel in a field crowded with layers of all types and prices? First, you cast a wide net (we started with 140 samples). Then you recruit testers who spend more time outside than in. Ours logged 700-plus trail days over six months. From Arizona to Iceland, we saw 186 days of rain (and plenty of sizzling sun) and temps from 5°F to 95°F. Our goal? Find the best three-season garb for every climate.