Arc'teryx Borderline Shirt

Wye Textile and Mesh Back Venting

The real story is the mesh-lined rear yoke. Arc'teryx placed ventilation exactly where a pack sits against your back. During hot climbs, this creates a noticeable cooling effect compared to solid-construction shirts. The collar holds its shape throughout the day, and the button-front allows easy ventilation adjustments mid-hike without breaking stride.

Relaxed Fit That Accommodates a Pack

Roll-up sleeve tabs sit at a comfortable position for half-sleeve wear during warmer stretches. The chest pocket remains accessible beneath pack straps without requiring awkward contortions. The hem is designed for untucked wear and hits at a length that looks clean with hiking pants or the Lefroy Pant.

Best Between 65 and 85 Degrees Under a Pack

Below 60°F, the same ventilation becomes a liability. Wind cuts through the mesh panel, and you'll notice cold spots across your upper back. Above 85°F, even the Borderline struggles, and a lightweight t-shirt with sunscreen becomes the better call. For moderate warmth where sun protection and pocket functionality matter, this is the sweet spot.

Arc'teryx Borderline vs. Peakline and Outdoor Research Astroman

The Outdoor Research Astroman Air LS offers a similar ventilated hiking shirt concept at around $85. The OR uses a different venting approach and runs slightly boxier through the torso. Both handle warm-weather hiking effectively, but the Arc'teryx's cleaner styling crosses over to casual settings better.

Pay for the Mesh, Skip It If You Don't Need It

Pair this with the Gamma LW Shorts for a warm-weather hiking setup, or the Lefroy Pant for full-leg coverage and UPF protection.