We asked an arctic explorer how to keep warm as temps drop. Here’s his best advice

Forget what you learned from Ralphie and Randy’s mother in A Christmas Story. You don’t have to be bundled up to stay warm when the temperatures drop. You just need to layer your clothes correctly. That’s why we asked Eric Lillstrom—an expedition guide with PolarExplorers—to teach us everything he knows about keeping warm in even the lowest temperatures on Earth. Lillstrom, who guides expeditions in parts of the world where dressing properly is a matter of life and death, says it’s all about the quality of layers—not the quantity.

“We have a full clothing and equipment checklist, and going over that list is the first thing that happens when we’re going on an expedition,” he says. “We lay out each individual piece and we spend an hour going over layering in detail. It’s all about making sure that you have everything you need without wearing too much.”

Lillstrom suggests that to stay warm all winter long, all you need are three (high-quality) layers.

The Base Layer

There are dozens of base layers out there, but it’s best to stick to the original: wool. “Professional guides are moving towards recommending all wool,” Lillstrom says. “There is nothing better than a high-quality wool layer.” Here are our favorites.

Smartwool Merino 250 Base Layer Crew Top
The purest of the wool base layers, Smartwool’s Merino 250 collection is made with 100% merino wool, featuring a heavier, softer knit that is still formfitting enough to wear under other, tighter layers. I ski all winter in this crew top, and swear by its always-warm, never-hot insulating capabilities. There are no itchy shoulder seams—and the seams that are present are flatlock stitched, so you’ll never have to deal with hot spots or prickly hems.

Smartwool Merino 250 Base Layer Bottom
The Smartwool Merino 250 bottoms are a near-perfect base layer for all of the aforementioned qualities of the crew top above, but are even more thoughtful—thanks to a multitude of cuts and sizing. If you ski often or wear tall boots, then you know how uncomfortable it is to have socks and long underwear fighting for real estate (and bunching up) in your boots. The 3/4-length bottoms put that problem to rest, leaving your ankles and shins free. This length is available for both men and women. Additionally, there are plus sizes and full-length options if that’s what you’re looking for.

Patagonia Capilene Air Crew Neck Shirt
If you prefer a wool blend to pure wool, then you can’t go wrong with Patagonia’s proprietary Capilene Air material. It’s an incredibly lightweight blend of merino wool and recycled polyester that is surprisingly warm for how thin and light it is. We love that it’s seamless (for added comfort—no scratchy seams), features stretchy sweater-like cuffs, and is more breathable than any base layer we’ve had before. And while a crew neck is incredibly versatile, we also love the hooded version of this shirt for added coziness.

Patagonia Capilene Air Bottoms
The matching bottoms to the above crew neck top, the Capilene Air Bottoms are as lightweight as long underwear can be. These aren’t as tight-fitting as some other brands, but the fit and weight give you an “I’m not wearing layers” feel.

The Insulated Layer

“This layer is essential to trap warmth in,” Lillstrom says. Plus, it’s the coziest thing you can have in your closet. Here are our favorite insulated layers.

Mountain Hardwear Ghost Whisperer 2 Hoody
I have had my Ghost Whisperer for six years and it’s still hands-down my favorite puffy for running errands, hiking, skiing, traveling, and just about everything else. It’s incredibly lightweight (I put mine into a stuff sack and carry it in my purse), super warm, layers perfectly, and looks amazing even after years of wear and tear. I recommend this puffy over all others.

Aether Apparel Women’s Senna Jacket
The design of the Senna Jacket is unbeatable. It’s retro, modern, sleek, and comfy all at the same time. And because of its design and water-resistance, it’s the perfect puffy to wear alone or as a layer. Aether set out to make the lightest, most stretchy goose-down bomber jacket—and it did.

Rab Men’s Cirrus Alpine Jacket
If you prefer wearing insulated layers that are animal-product-free, you can’t go wrong with any jacket featuring Rab’s recycled, high-loft synthetic insulation. It keeps you just as warm as traditional down, but forgoes the feathers and uses recycled insulation—meaning it has a minimal impact on the environment while delivering maximum warmth. The little details on this puffy, like the adjustable hem and stretchy cuffs, make it an instant favorite. Check out Moosejaw or Backcountry for additional sizes and colors.

The Weather-Proof Layer

Lillstrom explains that in ultracold conditions, you don’t have to worry about precipitation—so he prefers a wind-specific layer that isn’t waterproof. But for all of us who are subjected to drizzles and sleets during the winter months, there are shells that can protect against all the elements. Here are our favorite shell layers for both top and bottom.

Duer All-Weather Denim
Believe it or not, there are jeans out there that are made to protect you from wind, rain, snow, cold temperatures, and whatever else your day throws at you. Duer’s All-Weather denim has a wind- and waterproof membrane, a soft-to-the-touch lining, and reflective cuffs for extra visibility on dark mornings and evenings. They’re the most technical jeans I’ve found to date, but still look (and feel) good enough for everyday casual wear. It’s not often you find a pair of jeans you’d be okay getting stuck in a storm wearing.

Athleta Women’s Edgewater RainOut Parka
This waterproof, wind-resistant shell comes in three perfectly hued neutrals, has a flattering cut, an above-knee length, grosgrain finish, and lots of little features made to keep the weather out. What more could you want from a four-season shell?

Lululemon Rain Rebel Jacket
This knee-length jacket is the perfect weatherproof layer. It’s got a relaxed fit to accommodate whatever layers you have underneath, and features tape-sealed seams, zippered pockets, and reflective details. It’s waterproof and windproof, and we love the minimal design and six-hue color palette. We promise you’ll get compliments on this jacket.

Filson Men’s Cover Cloth Mile Marker Coat
Filson is a heritage brand known for making clothes that are tough enough for wildland firefighters, ranchers, and folks who spend their lives outside in some pretty extreme conditions. We love that this rain- and wind-repellent coat doesn’t have the shiny, plasticky look of modern shells. And its design is smart as hell. It has a generous fit to accommodate layering, or you can use the Filson button-on hood and zip-in liners to add insulation during winter months. This is a coat you’ll have for the rest of your life.

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