When a Rain Jacket Stops Breathing

A shell that says breathable can still turn you into a sauna. The membrane only moves moisture when the outside is cooler and drier than the inside, and on a humid climb that equation breaks down.

Know what to expect before you buy.

• Breathability drops hard in rain because the outer fabric wets out
• Mechanical vents under the arms move more air than any membrane
• Pit zips are the real hero of any hard effort
• Re-treat the DWR when water stops beading on the face

Layer thin and vent early. A breathable jacket is a tool, not magic, and it works best when you help it along.

On the next hard climb, open those pit zips before you feel sweaty. Keeping the shell dry from the inside out is the whole trick to staying comfortable all day.