Arc'teryx Cormac Crew Neck LS

The Arc'teryx Cormac Crew Neck LS uses 100% recycled Phasic LT polyester for running and hiking in cool to mild conditions. The fabric wicks moisture, dries quickly, and provides UPF 40+ sun protection for extended outdoor exposure. Flatlock seams prevent chafing during repetitive movement, and the regular fit allows comfortable layering.

I bought this for trail running on cool mornings and hiking when sun protection matters, but the weather doesn't require heavy layers. The Phasic LT fabric moves moisture away from the skin efficiently, helping prevent the shirt from becoming soggy during sustained activity. The recycled polyester content addresses environmental concerns without compromising performance.

Recycled Phasic LT Polyester with UPF 40+

The Phasic LT polyester uses a lightweight construction optimized for moisture management during activity. The fabric dries faster than cotton and most wool alternatives while providing UPF 40+ sun protection. The recycled content comes from post-consumer plastic processed into performance fibers.

Arc'teryx designed the flatlock seams to sit smoothly against skin during extended wear. Traditional overlocked seams can cause chafing during repetitive arm movement, especially when wet. The flatlock construction eliminates this issue for running and hiking applications.

How Does the Arc'teryx Cormac Crew Neck LS Fit?

The regular fit provides room for movement without excess fabric. At just over 6 feet and 165 pounds, I wear a size L with a comfortable, non-restrictive fit. The torso has enough room for natural movement during running without being baggy enough to flap in the wind.

The sleeve length reaches the wrist with slight extra length for thumb coverage during activity. The crew neck sits comfortably without being too tight. The hem drops below the hip and stays tucked reasonably well during running, though aggressive movement can pull it loose.

Best Between 45 and 65 Degrees

This works best for cool to mild conditions, 45-65°F, during running and hiking. The long sleeves provide sun protection and warmth without the weight of insulated layers. The moisture-wicking fabric effectively handles moderate sweat output.

For hot weather above 70°F, the Ether Crew short-sleeve provides better cooling. For cold weather below 40°F, this works as a baselayer under insulating midlayers. The Cormac occupies the transition zone between warm-weather shirts and cold-weather base layers.

Arc'teryx Cormac LS vs. Ether Crew and Patagonia Capilene

The Ether Crew uses Helius polyester in a short-sleeve design for warmer conditions. The Cormac LS provides more coverage and slightly more warmth for cooler-weather running.

The Patagonia Capilene Cool Daily LS offers similar performance at a lower price. The Arc'teryx Phasic LT fabric feels slightly smoother against skin and has marginally better moisture management.

Premium Pricing for Running-Specific Performance

For dedicated running and hiking in cool conditions where moisture management and sun protection matter, the Cormac delivers. The Phasic LT fabric performs well, the flatlock seams prevent chafing, and the recycled content adds environmental value. The regular fit works for both activity and casual wear.

The price sits at the premium end of the technical long-sleeve shirt market. For occasional trail use where performance isn't critical, cheaper options work adequately. For regular running and hiking where moisture management affects comfort, the Cormac's performance justifies the cost.

For other running gear, see the Cormac Shorts and Norvan LD3. The best beanies for running cover headwear for cold-weather training.