Layering for 5 to 50 Degrees Without Looking Like a Sleeping Bag

If you are warm at the trailhead, you are wearing too much. If you are cold after ten minutes, you are wearing it wrong.

Layering sounds like a sales pitch, but it is simple physics. You make heat when you move. Sweat is what chills you when you stop. Everything about dressing for the cold comes down to moving moisture out and keeping warm air in, and being able to change that quickly.

The three jobs

• Base layer: moves sweat. Thin wool or synthetic, right against your skin. No cotton, which holds water and drains heat.
• Mid layer: holds warmth. Fleece or a light puffy. Zippers are your friend because they let you vent.
• Shell: stops wind and wet. A jacket that stays out of the way until the weather turns.

What we wear, by temperature

These are starting points for moving hard. Everyone runs differently, and wind, wet and elevation change the math.

• 50 degrees: base layer top and hiking pants. Light shell in the pack.
• 30 degrees: base layer, light fleece, shell in the pack, hat and thin gloves.
• 15 degrees: base top and bottom, fleece, windproof shell, warm hat, real gloves.
• 5 degrees: all of the above, plus a heavier mid layer, a face cover and mittens over liners, and a big puffy for every stop.

The rules of the trail

1. Start a little cold. You will warm up in ten minutes.
2. Take a layer off before you sweat, not after.
3. Put the puffy on the moment you stop, before you feel cold.
4. Keep your hat and gloves where you can reach them.
5. Change your socks at lunch if your feet are damp. It feels like a five-star hotel.

Watch for trouble

Numb fingers or toes, pale patches of skin, nonstop shivering, slurred speech and bad decisions are all warning signs. Stop, warm up, and get out. If someone in your group gets confused in the cold, treat it as a real emergency and call for help.

About looking like a sleeping bag

You are going to look a little like a sleeping bag. We have made peace with this. If you add one thing, a No Lukewarm beanie at least tells people it was deliberate.