Layering Clothes for Hiking: Base, Insulation and Shell
Hiking produces heat on climbs and very little at rest stops, while weather can change within an hour. A layering system lets you add or remove clothing quickly so you stay warm without soaking your clothes in sweat.
The base layer
The base layer sits against your skin and moves moisture away from it. Synthetic fabrics and merino wool both work well, while cotton holds water and chills you once you stop moving.
Choose a weight that suits the season: light for warm days, heavier for cold ones.
Insulation and shell
Insulating layers such as fleece, down or synthetic jackets trap warm air. Down is light and compressible but loses warmth when wet; synthetic insulation keeps more warmth when damp. The outer shell blocks wind and rain, and should be breathable enough to let some moisture escape.
Carry a warm layer even on mild days, because rest stops, injuries and delays happen.
Pit zips, front zippers and a vest give you room to adjust without fully stopping, which keeps the group moving at a steady pace.
Adjusting on the move
Start a climb slightly cool, since you will warm up quickly. Remove a layer before you start sweating heavily and add one as soon as you stop for a break, not after you feel cold.
Hats, gloves and zip vents give fine control with little effort, and keeping a dry layer for camp makes evenings far more comfortable.