A top-performing baselayer is worth more than its weight in gold. You can easily swap out midlayers or shells on the fly, but once you don your base it better be a good one, because you probably aren’t changing it mid-mission. If you want the security of breathable warmth that moves with you and will regulate your temperature, there’s no better choice than merino wool. And Smartwool‘s baselayers are the most robust and reliable of any we’ve tried. These garments are designed with care, by people who are out in the harshest elements and understand what’s needed to keep you comfortable so you can spend more time in nature.

smartwool merino 250 baselayer 3 4 bottoms women s — Women’s Merino 250 Base layer 3/4 Bottom. Photo: Smartwool

Their extensive Merino 250 midweight base layers (available for men and women) serve for all your cold-weather adventures. We tried the redesigned 3/4 Bottoms, which are handy to keep your ski boots, hiking boots, and running shoes free of bulk and friction. 100% responsibly sourced Merino wool provides ultimate breathability and comfort, while reducing sag and excess fabric—ideal for layering. If we had to pick one feature we like above all others, it’s the wide, Merino-lined waistband that never pinches.

Features

100% Merino wool fabric made with an interlock knit for enhanced comfort, breathability, thermoregulation, and odor resistance
Fit updated to improve functionality while enhancing aesthetics
Merino-covered elastic waistband and traditional fly design
Flatlock seam construction designed to minimize chafing
100% Merino Wool; Exclusive of decoration.

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As for the original Smartwool specialty—socks—we like their PhD® Ski Light Elite (available for men and women), designed to fit in ski boots.

Smartwool Womens PhD Ski Light Elite — Women’s PhD® Ski Light Elite. Photo: Smartwool

With a lightweight build, the Women’s PhD® Ski Light Elite provides you with targeted cushioning on the shin, ball, and heel for protection without bulk in tight-fitting boots. These over-the-calf socks feature Smartwool’s Indestructawool™ technology for enhanced durability, their 4 Degree™ elite fit system for a performance-ready fit, and the Virtually Seamless™ toe for in-boot comfort. They are designed with a wider welt to help ensure the perfect fit, and mesh zones help keep things breathable and dry.

Features