Patagonia Merino Air Base Layer

Jun 09, 2023

Lighter, softer, and more stylish than we thought possible for a performance top

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Patagonia’s gossamer new base layer is insanely light and airy, but, thanks to a new manufacturing technique, it’s just as warm as its heavier competitors.

Here’s what Patagonia says about the manufacturing process:

The wool for each garment is…treated using an innovative air-jet process that creates yarn of greater loft and insulation value than conventionally spun wool. Using a computerized knitting machine, the lofted wool and 100% recycled-polyester yarns are knit directly into a seamless performance fit garment with minimal waste.

Translation? The company used a high-pressure air gun to magically boost the wool’s thickness and warmth without having to add more material. That means you get a toasty base layer that’s lightweight and super breathable—best for high-output activities in temperatures ranging from 30 to 60 degrees. The efficient “knitting machine” both eliminates seams, which can cause chafing, and reduces waste: there’s only four grams of leftover fabric from each Merino Air, Patagonia says.

We wouldn’t believe the marketing speak if we hadn’t tested the base layers ourselves. We took the Merino Air on an overnight climbing trip this summer and found that we never wanted to take it off. “It’s amazingly warm for how light it is,” says Outside associate editor Meaghen Brown. “But it doesn’t have that heavy feeling of other wool base layers.”

It gets bonus points for its stylish cut (we love the hood and loose neck, although it’s also available in a crew version) and color accents at the wrists and hem. In fact, it looks and wears more like an après sweater than a performance base layer.

And, because we’re talking about Patagonia, the merino wool is harvested from sustainably run grasslands in Argentina and the polyester is 100 percent recycled.

$149, patagonia.com