Hiking my first 14er was the first time I learned that “cotton kills.” Thankfully, I didn’t actually die. I was 16 at the time, on top of Longs Peak, one of Colorado’s 53 peaks over 14,000 feet high, a.k.a., 14ers. And I learned the hard way how much colder it can be at 14,000 feet than 8,000—and that wearing a cotton shirt soaked with sweat while a storm is rolling in is a surefire way to feel uncomfortable. I ripped my jeans, shivered on the summit and had to borrow a stranger’s water filter because my bottle was empty before I even reached the top, but like many people, I desperately wanted to do more. And 20 years later, I can happily say I’ve ticked off several more 14ers around the state—a few of them many times, including at night, in the winter, running or by more technical routes. I’ve learned a few things—I rarely wear cotton t-shirts up there, for one—and I’m always excited to meet people who are heading up their first 14er. If you’re planning your first 14er, here’s how to layer for maximum comfort.\n\nStart with synthetic or wool underwear. Even if you have high-quality hiking pants or a fancy wicking shirt, if your underwear or bra is cotton, it’s going to stay wet once it gets sweaty, and that will probably make you cold on top.\n\nShorts might be OK—but with tights or pants, you’ll be certain to be comfy. In the height of summer season, with perfect weather, you can probably get away with wearing running shorts (I personally love the Zendo Shorts) or synthetic soft shell hiking shorts if I want more pockets. But it’s likely to be chilly on top, and the sun’s exposure is much more harsh that high above sea level, so I often opt for breathable, lightweight tights like the Essentia Tights, the Vantage 7\/8 Leggings, or soft shell pants like the Voodoo Pants or Ferrosi Pants. These have great stretch, for taking the big steps, and the soft shell pants are abrasion-resistant, in case you think you might do any butt-scooting, like I did my first time descending Longs Peak.\n\nSHOP WOMEN'S BOTTOMS\n\n\n\nOn top, start cold. Another lesson I’ve learned since my first 14er is that it’s best to start your hike dressed in lighter layers than what would be comfortable just standing still. You might be starting in the dark, early in the morning, and if it’s cold, you’ll be tempted to start in a jacket. But if you take one layer off before you start moving, you’ll avoid getting overheated as soon as you exert yourself with the uphill hiking. So “start cold,” and keep from having to shed a layer almost immediately—and probably breaking a sweat earlier than you need to. For my shirt layer, I love the Echo Hoody. It’s quick-drying and the loose hood protects my arms, neck, ears and head from that intense high-elevation sun. I also love layering an Echo Tee or Echo Tank with a super-light Optimist Sun Hoody—or the Vigor Hybrid Hooded Jacket if it's chillier out. It’s a perfect combo for going a little bit more light and fast.\n\nPack a puffy for the summit. Even if it looks sunny and warm when you’re starting out—the breeze will be cooler on top of the mountain. In fact, for every thousand feet of elevation you climb, the temperature will drop about three degrees. And who wants to be uncomfortable when you finally get to the top and see the view? That’s when you want to relax, take photos, and enjoy the most scenic snack spot! I always pack a down jacket like my Illuminate Down Hoody and usually put it on as soon as I get to the top, to hold in my warmth. If the weather’s nice, I don’t want to feel rushed to hike down because I’m cold. And since down jackets packs down tiny, there’s no reason to leave them behind.\n\nSHOP WOMEN'S DOWN JACKETS\n\n\n\nAlways, always pack a rain jacket. Barring an accident or a lightning strike, getting soaked by a rainstorm on a 14er is one of the quickest ways to have your fantastic day go south. And since rain jackets, like the Helium II Jacket, weigh next to nothing, you can forget it’s even in your pack, until you actually need it. It’s an insurance policy I don’t head up a 14er without. Plus, if weather gets really gnarly, you can layer it over your puffy.\n\nSHOP WOMEN'S RAIN COLLECTION\n\nDon’t forget your extremities! It’s truly amazing what a pair of light gloves can do for morale. Even when I wear shorts, I pack a pair of Backstop Sensor Gloves or Overdrive Convertible Gloves, because when it gets chilly up high, I don’t want to be fumbling with my zippers or my snack wrappers with frozen fingers. In case my ears are cold, too, I pack a lightweight stocking cap, like the Wind Pro Hat. And I’m almost always wearing my Performance Trucker Trail hat. It’s streamlined and adjustable, so it doesn’t fly off my head like other truckers do in the wind. It’s also quick to dry, keeps the sun out of my eyes, and keeps my flyaway hairs under control.