I was naked, wet, alone, and shivering inside of my down sleeping bag, perched precariously on the banked side of a mud-strewn switchback about halfway up Saddle Peak in the Santa Monica Mountains. “Is it safe to sleep in these conditions?” I wondered. “How long before I become hypothermic?”

Before I knew it, I had packed up my camp quicker than ever before and was bailing from my thru-hike, a jolt of adrenaline coursing through my veins as I slid down the trail and walked along the road until I had enough cell service to call a friend to come pick me up. It was only 45 degrees outside, but my adventure was ruined. And it was all because I didn’t know a thing about fabrics.

When you’re first starting out backpacking, knowing what to buy and what to skip can feel overwhelming. The clothes you wear on your back may seem simpler to figure out than what stove or tent to purchase, but backpacking clothes have a history of great ideas hidden in their design. The more you learn about what to wear and why, the more likely you are to be prepared and have way more fun when you’re out in the wild.

I don’t want to scare anyone off with the promise of a scientific deep-dive into fabric and layering strategy, so for the moment, I’ll level with you. When backpacking, you are protecting against two main factors: wet and cold.

Rain and other forms of moisture are surprisingly easy to protect against cheaply, thanks to the magic of plastic garbage bags. Had I done a bit more research before my Backbone Trail thru-hike, I would have known to store my down sleeping bag and all my clothing inside a dry sack or sealed garbage bag, leaving me with warm, comfy options for nighttime, once my camp was set up. I also would have known not to jump into a down bag with wet clothes on in an effort to warm up. Lastly, since I knew the weather forecast ahead of time and knew that it was going to dump buckets of water onto me for two straight days, I should have splurged on a pair of rain pants to avid freezing legs! The one thing I did do correctly was pack an extra pair of warm, wool socks.

This leads me to my next point – it’s good practice to always wear wool or synthetic on the trail, never cotton. There’s a saying in the hiking community: “cotton kills.” Personally, I find the sentiment to be a tad melodramatic, but it comes from a place of good intentions. When cotton absorbs moisture via snow, rain, or the sweat on your body, it ceases to provide warmth via its thousands of tiny air pockets. That means that if the air outside is colder than your body temperature, you’re going to get a chill, and, if it’s near freezing or you stop moving for a long enough time, your core temperature can drop way down, causing hypothermia, and, in extreme cases, death. Other fabrics to avoid (for similar reasons) include: corduroy, denim, rayon, silk, modal, viscose, bamboo, lyocell, and tencel.

Cotton, however, is great for warm days at the crag or hot, dry days spent backpacking through the desert. Its ability to trap moisture acts like a mini-swamp cooler for your body. I’ll frequently hike in a cotton tank top when it’s sunny out and I know I’ll be broiling and sweaty all day.

For this reason, I’m a huge fan of wool products when it comes to choosing shirts, socks, and base layers. Wool wicks moisture away from your skin and towards the outer layer of the fabric. Plus, it continues to insulate even when wet, which means you won’t be stuck shivering on the side of a cliff, wishing you were home watching Rick and Morty. If you’re worried about the concept of wearing gross, itchy sweaters in the wild, like the ones your grandma used to make, then fear not! Wool has come a long way in recent years, with most companies opting to use Merino Wool for their products, due to its ultrafine, ultra-non-itchy fibers. Fun fact – wool is also naturally odor-resistant, making it the sexiest choice for thru-hiking or trekking with that special someone.

When I was first starting out as a fledgling mountaineer, I was lucky enough to have mentors who walked me through the basic strategy for layering to stay warm in the wilderness. Thank goodness, the process is roughly the same across all sports, whether you’re snow camping, climbing a mountain, or going on a ski trip with your folks.

On top, you’ll want to wear a wool or synthetic base layer (make sure it’s flush against your skin – no secret tanks or cotton bras!), then an insulated mid layer (usually a fleece or thin jacket), and finally, a big, puffy outer coat for when it’s below freezing. If you know you’re going to be in wet or windy conditions, layering a rain jacket or alpine shell on top of all this is a crucial last step. Many companies offer a 3-in-1 jacket that combines everything I mentioned except the base, making it a simple and money saving solution for winter wear. On my head, I like to make sure I have a base layer with a hood (incredible protection on windy days) paired with a fleece-lined wool cap. On the bottom, it really depends on my activity for the day. I’ll wear waterproof snow pants for skiing or big snow hikes, but if I’m thru-hiking or temperatures are milder, I like to go with a wind and water resistant hiking pant (paired with a thermal legging for frigid, winter treks). This gives me the versatility of wearing one or both, as needed.

By now, you may be wondering if a wool or synthetic base layer is best for you. Worry no more, gentle reader! I’m here to dispel my knowledge.

As I mentioned before, a Merino Wool shirt or base layer set is going to be warm, soft, moisture-wicking, insulating when wet, non-itchy, and odor resistant. If it likes you, it may even spoon you and sing you to sleep. The only real drawbacks are wool’s slight lack of durability over multiple years of use and the fact that it will absorb over 30% of its weight in water, making it a bit less efficient at wicking/insulating than synthetic. A synthetic base layer, on the other hand, will wick moisture away from your skin like a dream, giving it a drier feel. It’s also more durable than wool and less odor-resistant, so be prepared to buy your tent-mate a drink if you opt for the manmade stuff.

When selecting an insulated outer layer, you’ll likely come across a slew of down and synthetic options. Like with base layers, there are pros and cons to each, and this logic applies to sleeping bags as well. Down is rated by its fill-power, which relates to the loft of the tiny feathers and their ability to trap heat. A 600-fill down jacket means that one ounce of down fills 600 cubic inches of space. High-quality down can be rated at 800 or even 900-fill power, meaning that you get more warmth for less weight and even more compressibility. Down is quite durable and the warmest material available, relative to its weight. However, it loses its ability to keep you warm the moment it gets wet and begins to clump up.

Most companies have begun to combat this by coating their down with a hydrophobic additive that makes the duck feathers more water-resistant. It isn’t a perfect solution, but it will keep you warm in the face of a light rain or the dreaded tent condensation. If you’re car camping somewhere wet or really trying to save some cash, synthetic might be worth a look, but if you’re pushing big miles on the trail or doing a multi-day backpacking trip, down is the way to go.

I’m happy to report that I haven’t had another horror story like my hypothermic Malibu evening since I began reading about layering strategies and investing in good quality clothes that will last for the next decade. When I hiked the Inca Trail in 2017 with my mom, the sky flooded onto our group for three straight days. The entire trek is basically a high-elevation romp through cloud forests and Andean mountain passes, meaning that weather and temperatures can vary wildly. I was hiking the trail without a porter, meaning that I was responsible for my clothing, water, snacks, and all my gear beyond the tent, and I’m pleased to say that my research and mishaps finally paid off!

I kept my clothes and sleeping bag dry during the day, which meant I had extra warm socks and thermals to switch into every night and a comfy, down bag to crawl into when it was time for sleep. Trust the garbage bag theory, people. It saved my life in Peru.

When I visited Ecuador last July, I was able to put my outdoor fashion skills to the test once again when I climbed to 16,818 feet above sea level on Illiniza Norte. The Incan weather gods decided to throw me a curveball in the form of a whiteout, with freezing rain pelting my group for the entirety of the ascent. We climbed from high Polylepis forests into a barren, alpine wasteland on a small rope team of three. It was likely in the teens with the wind chill, and I managed to stay relatively warm and dry by putting my head down and committing to the layering strategy mentioned above.

Wool socks, waterproof gloves, thermals, hiking pants, an insulated mid layer, down jacket, and alpine shell all worked together at different moments of the climb to regulate my temperature. When we stopped to eat lunch in a refuge, the down jacket came off. When the wind whipped around and stung my face like a thousand porcupine quills, I pulled my jacket and shell hoods up. I was ready for anything.

I would be remiss if I didn’t leave you with one final piece of advice from the field – don’t forget about sun protection! I got away with hiking in cheap sunglasses from the gas station for far too long before one fateful day on Mt. Whitney really freaked me out. After descending the infamous 99 switchbacks in full sun on an October afternoon, I noticed my vision begin to narrow. I got dizzy and found it hard to focus, eventually stopping to eat some food on a few boulders. Part of the issue is that I was bonking from not getting enough nutrition, but my eyes were also beginning to blur after having way too much of the rough sun.

It’s easy to forget that sun doesn’t just come from above; it reflects back up at your face when you’re hiking on any light-colored surface like snow, sandstone, or granite. For this reason, you should always wear a sun hat and invest in a pair of polarized glasses! I found a surprisingly affordable pair of “sport” sunglasses on Amazon that wrap around my face, protecting my eyes on all sides from the exposure. Lastly, not to sound like a mom or anything, but don’t leave the house without sunscreen! Your skin will thank you when you’re 50.

It is my sincere belief that good layers are the key to staying safe and enjoying yourself outdoors. You don’t have to spend a fortune to get quality pieces, either! As I mentioned in Part 1 of this series, sites like steepandcheap.com and REI Garage have provided me with some incredible finds (no to mention REI’s amazing return policy). Don’t be afraid to experiment and make mistakes when you’re just starting out – we all do it!

Once you solidify your clothing game plan, you’ll be able to enjoy the outdoors in the middle of a winter hailstorm and cackle at the darkening clouds above, exclaiming, “Bring it on!” Or you could just go on an early spring hike in the woods with your dog. That’s pretty nice too.

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