Choose layers that work together to channel perspiration and condensation away from your skin so you don’t feel clammy and gross. Don’t wear a cotton tank under a wool midlayer, for example, or vice-versa: wool wicks moisture away from your skin, and cotton doesn’t. Mixing these layers inhibits wool’s natural wicking and insulating properties.
Half-zips are key.
The more opportunities you have to vent, the better. Choose layers with half- or quarter-length zippers to release heat from your core so you don’t overheat.
Use your pit zips.
Unless you’re hiking in horizontal rain, keeping your pits unzipped isn’t likely to expose you to too much, if any, water. Don’t use these vents sparingly. They’re there to keep you cool and allow water vapor to escape before you drench your layers in sweat. You’ll stay drier if you use pit zips over the main zipper on your rain shell, and you’ll find them to be more comfortable and less noticeable than you might assume at first.
Get a cold start.
If you’re warm and cozy when you…