Ask any Colorado local and they’ll say the same thing: layering is the whole game, and it starts against your skin. The base layer’s job is to pull sweat off you and keep you warm even when damp — because at 10,000 feet, wet and cold is how a great day goes sideways. Here are the base layers we trust at every budget, plus how to choose.
Our base-layer picks at a glance
Every pick below, budget to premium, side by side:
Best-value merino sets
Complete top-and-bottom merino at a friendly price — where most people should start.
Merino midweight top & bottom set — best value
A full top-and-bottom merino set at a friendly price: wicks sweat, fights odor over multiple wears, and stays warm when damp. The easy first base layer.
- QUALITY MIDWEIGHT BASELAYER: 100% Merino Wool is super soft and extremely comfortable. This three season merino crew neck thermal has the versatility and warmth to make this an essential part of your outdoor gear. Made to fit sizes XS to 6XL and Tall Sizes M-Tall to 4X-Tall (4XL to 6XL and Tall sizes in Black Only) Minus33 offers the largest size selection. Outfitting anyone from the Hard-at-Work to the Hard-at-Play.
- PERFECT TO WEAR FOR: any adventure. That would be skiing, snowboarding, hiking, camping, or just everyday wear, This shirt is breathable so you don't have to worry about over heating or sweating through it since it has moisture wicking properties. Our crew has tagless construction so you don't have to worry about the annoyance of the unwanted itch. You can wear this long sleeve as a base layer, mid layer, or even outer layer so you can get as many uses out of it as you would like!
- EXPERIENCED BRAND: Although there are many copy-cats on the market today, Minus33 has been a trusted brand since 2004. We see it all – from beautiful fall leaves, to white, snowy winters, to colorful springs and summers. We’re New Englanders, plain and simple. We’ve been hiking, camping, skiing, and everything else in between since we were kids. No amount of snow keeps us down, and we only continue to thrive in the summer.
- IMPORTED: As the legacy of a 100+ year old USA based woolen company, Minus33 knows quality and comfort in Merino Wool. We are committed to bringing you the best Merino Wool products at a reasonable price.
- TECHNICAL DETAILS: 100% 18.5 Micron Merino Wool 235 g/m2 Interlock knit construction with flatlock seams. Garment Weight Size Large = 11.2 oz. (315 grams). UPF Rating 50+
Merino base-layer set (top & long johns)
Another complete-set option in soft next-to-skin merino — great value if you want head-to-toe coverage in one buy.
- Midweight: Mens Merino Base Layer Available in: Lightweight = 165 g/m², Midweight = 250 g/m², Heavyweight = 320 g/m². Free Merino Wool Hiking Socks ($21 Value) – Package includes Midweight Merino wool base layer mens top and wool men long johns 250 g/m² + Merino Wool Hiking Socks. Cool Packaging. Makes A Great Gift.
- Super Soft & Comfortable: 100% Superfine 17.5 Micron merino wool base layer set mens provides all day comfort and no itch! Merino wool long underwear men set was designed for daily wear without rubbing, overheating, or bunching of regular cotton.
- Moisture Wicking & Odor Resistant: Natural wicking and odor-resistant properties of merino wool thermal underwear allow it to absorb moisture better than any other fabric, keeping you dry and fresh.
- Breathable – For longer lasting wear, hand wash and lay flat to air dry. Mens wool long johns sets naturally regulate body temperature to keep you comfortable all year round.
- Zero Worries: Every we make merino wool base layer top mens and long johns are backed by our Merino.tech Promise - ensuring you're 100% happy with every Merino.tech purchase. For best results hand wash and lay flat to dry
Merino long-sleeve crew — budget top
A standalone merino crew for layering under a ski shell or around town. Buy the weight to match your day.
- QUALITY MIDWEIGHT BASELAYER: 100% Merino Wool is super soft and extremely comfortable. This three season merino crew neck thermal has the versatility and warmth to make this an essential part of your outdoor gear. Made to fit sizes XS to 6XL and Tall Sizes M-Tall to 4X-Tall (4XL to 6XL and Tall sizes in Black Only) Minus33 offers the largest size selection. Outfitting anyone from the Hard-at-Work to the Hard-at-Play.
- PERFECT TO WEAR FOR: any adventure. That would be skiing, snowboarding, hiking, camping, or just everyday wear, This shirt is breathable so you don't have to worry about over heating or sweating through it since it has moisture wicking properties. Our crew has tagless construction so you don't have to worry about the annoyance of the unwanted itch. You can wear this long sleeve as a base layer, mid layer, or even outer layer so you can get as many uses out of it as you would like!
- EXPERIENCED BRAND: Although there are many copy-cats on the market today, Minus33 has been a trusted brand since 2004. We see it all – from beautiful fall leaves, to white, snowy winters, to colorful springs and summers. We’re New Englanders, plain and simple. We’ve been hiking, camping, skiing, and everything else in between since we were kids. No amount of snow keeps us down, and we only continue to thrive in the summer.
- IMPORTED: As the legacy of a 100+ year old USA based woolen company, Minus33 knows quality and comfort in Merino Wool. We are committed to bringing you the best Merino Wool products at a reasonable price.
- TECHNICAL DETAILS: 100% 18.5 Micron Merino Wool 235 g/m2 Interlock knit construction with flatlock seams. Garment Weight Size Large = 11.2 oz. (315 grams). UPF Rating 50+
Premium picks — Smartwool & Minus33
Softer, longer-lasting merino from the brands that made their name on it. Buy once, ski for years.
Smartwool Classic Thermal Merino crew (men’s) — the benchmark
The gold-standard midweight merino top: soft, warm, odor-resistant, and built to last seasons. If you ski a lot, this is the one you’ll reach for all winter.
- Our slim fit is intended to follow the contours of the body Fabric helps combine the moisture management, temperature regulation, and odor resistance of 100% Merino wool with interlock knit for comfort Flatlock seam construction and offset shoulder and side seams designed to help increase comfort and minimize chafing Side seams wrap to front
Smartwool Classic Thermal Merino bottoms (men’s)
The matching bottoms — midweight merino that layers slim under ski pants without bunching, and stays warm even when you’re working hard.
- 100% Merino Wool
- Made in the USA
- COLD WEATHER BASE LAYER. Keep your ski or hiking boots free of bulk and friction with our 3/4 Bottom. Merino wool provides ultimate comfort, while a newly redesigned base layer pants fit helps reduce sag and excess fabric—perfect for layering.
- SLIM FIT. Designed to meet the demands of outdoor adventuring, these slim fit bottoms show off a slimming silhouette while offering unrestricted movement through the legs. Inseam: 21.5"
- CLASSIC THERMAL MERINO. Ideal for cold-weather activities where warmth and breathability are crucial, this midweight fabric used a Merino wool construction that helps move moisture away from skin to keep you warm and dry.
Minus33 midweight merino bottoms
100% merino at a friendlier price than the big brands — warm, itch-free, and a smart value premium bottom.
- QUALITY MIDWEIGHT BASELAYER: 100% Merino Wool is super soft and extremely comfortable. This three season merino wool thermal bottom has the versatility and warmth to make this an essential part of your outdoor gear. Fits sizes XS to 6XL and Tall Sizes M-Tall to 4X-Tall (4XL to 6XL and Tall sizes in Black Only) Minus33 offers the largest size selection. Outfitting anyone from the Hard-at-Work to the Hard-at-Play.
- WEAR THESE FOR ANYTHING: Hiking, running, camping, overlanding, hunting, ice fishing, skiing, snowboarding, snowshoeing, the activities are endless. Wear this base layer under your clothes for cold weather or just wear them by themselves to lounge around. These thermal long johns are perfect for three season wear. Fall, winter, and spring. Designed to keep you warm, dry, and ready for hours of outdoor fun!
- EXPERIENCED BRAND: Although there are many copy-cats on the market today, Minus33 has been a trusted brand since 2004. We see it all – from beautiful fall leaves, to white, snowy winters, to colorful springs and summers. We’re New Englanders, plain and simple. We’ve been hiking, camping, skiing, and everything else in between since we were kids. No amount of snow keeps us down, and we only continue to thrive in the summer.
- TECHNICAL DETAILS: 100% 18.5 Micron Merino Wool 235 g/m2 Interlock knit construction with flatlock seams. Garment Weight Size Large = 9.6 oz. (272 grams). UPF Rating 50+
- IMPORTED: As the legacy of a 100+ year old USA based woolen company, Minus33 knows quality and comfort in Merino Wool. We are committed to bringing you the best Merino Wool products at a reasonable price.
Women’s picks
Cut for a woman’s fit — a complete set or mix-and-match top and bottom.
Merino.tech women’s base-layer set (top + bottom)
A complete women’s merino set in a single buy — superfine, non-itchy fibers in multiple weights. The easy women’s starting point.
- Heavyweight: Womens Merino Base Layer Set Available in: Lightweight = 165 g/m², Midweight = 250 g/m², Heavyweight = 320 g/m². Merino Wool Hiking Socks ($21 Value): Package includes Heavyweight Merino wool base layer top, Merino Leggings 320 g/m² + Merino Wool Hiking Socks. Cool Packaging. Makes A Great Gift!
- Super Soft & Comfortable: 100% Superfine 17.5 Micron women merino base layer set provides all day comfort and no itch! Designed for daily wear without rubbing, overheating, or bunching of regular cotton.
- Moisture Wicking & Odor Resistant: Natural wicking and odor-resistant properties of merino wool thermal underwear women allow it to absorb moisture better than any other fabric, keeping you dry and fresh.
- Breathable: For longer lasting wear, hand wash and lay flat to air dry. Womens merino wool base layer top and bottoms set naturally regulates body temperature to keep you comfortable all year round.
- Zero Worries: Every Merino.tech Merino Wool Base Layer Women Set we make is backed by our Merino.tech Promise - ensuring you're 100% happy with every Merino.tech purchase. For best results hand wash and lay flat to dry
Smartwool Merino 250 top (women’s) — warmest weight
Smartwool’s warmest everyday merino, cut for women. The pick for cold chairlifts and deep-winter days.
- Odor-resistant
- Temperature regulating
- Will help keep you cool when your intensity amps up, and its design helps minimize chafing
Smartwool Classic Thermal bottoms (women’s)
Midweight merino bottoms for women that layer smoothly under ski pants — warm, breathable, and made to last.
- Our slim fit is intended to follow the contours of the body Four-way stretch knit fabric puts softbrushed Merino blend next to skin and recycled synthetic material against the elements to help balance comfort and protection Fitted with a mid-rise waist Drop-in hand pocket and secure pocket on back Reflective elements
- Four-way stretch knit fabric puts softbrushed Merino blend next to skin and recycled synthetic material against the elements to help balance comfort and protection
- Windproof front panel (0 CFM rating): Non-PFC DWR finish helps protect from the elements Merino-encased elastic waistband designed for comfort keeping merino blend next to skin Two secure external pockets Reflective elements
How to choose a ski base layer
- Material — go merino. Warm, warm-when-damp, and odor-resistant so you can re-wear it for days. Synthetics are cheaper and dry faster but hold smell. Never cotton.
- Weight — midweight for most. The all-rounder for resort days; lightweight if you run hot or ski spring slush, heavyweight (like Smartwool 250) for very cold days.
- Fit — snug, not loose. Close to the skin so it wicks, but not compression-tight — you want a smooth layer for your mid and shell to glide over.
- Budget vs. premium. A value merino set is plenty for occasional days; premium Smartwool/Minus33 is softer, warmer for its weight, and lasts far longer if you ski a lot.
Complete the base: ski socks
Your feet need the same treatment — one good merino ski sock, never thick or doubled.
Merino ski socks
Over-the-calf merino wicks and cushions in a ski boot. Wear one thin-to-midweight pair — never thick or doubled, which cuts circulation and makes feet colder.
- 30% MERINO WOOL, 35% ACRYLIC, 20% NYLON, 6% POLYESTER, 6% ELASTANE, 3% RUBBER
- Imported
- 30% Merino Wool For Extra Warmth and Comfort: Softer and finer than regular wool, Merino provides soft and itch-free comfort against the skin. Its natural temperature regulation keeps you warm in the cold and wicks moisture, ensuring all-day comfort in any season. Merino Wool Ski Socks deliver exceptional wearing experience during long time in cold weather.
- Good Breathability Keeps Dry & Odorless: Made with moisture-wicking merino wool, these sport socks pull sweat away and promote airflow to keep your feet dry and odorless. Stay dry and fresh all day long. They' re perfect for skiing, snowboarding, or staying cozy in cold weather.
- Over-the-Calf & Seamless Toe Design – The over calf length offers added warmth and support for your calves, while the seamless toe reduces friction and helps prevent blisters. The non-slip cuff keeps the ski socks securely in place without sliding down, ensuring a perfect fit inside your over-the-calf ski boots.
Smartwool ski socks
The benchmark ski sock: targeted cushioning, merino warmth, over-the-calf coverage. Worth it for the fit alone.
- 4 Degree elite fit system for a dialed-in, performance-oriented fit. Indestructawool technology for enhanced durability
- SW001911
- Virtually Seamless toe for enhanced comfort. Shred Shield technology reduces wear from toes.
- Sock Height: Over-the-Calf. Sock Cushion: Targeted Cushion
Base layers for skiing FAQ
What is the best base layer material for skiing?
Merino wool for most skiers — warm, warm even when damp, and naturally odor-resistant so you can re-wear it over a trip. Synthetics are cheaper and dry faster but hold smell. Avoid cotton entirely.
Is premium merino like Smartwool worth it over a budget set?
If you ski occasionally, a value merino set is plenty. If you ski a lot, premium merino (Smartwool, Minus33) is softer, warmer for its weight, and lasts far longer — often cheaper per season. Buy to match how much you’ll use it.
What weight base layer do I need for Colorado skiing?
Midweight is the all-rounder for typical resort days. Go lightweight if you run hot or ski spring slush, and heavyweight (like Smartwool 250) for very cold, low-output days.
Should ski base layers be tight or loose?
Snug and next-to-skin so the fabric can wick — but not compression-tight. You want a smooth layer for your mid layer and shell to slide over without bunching.
Are women’s base layers different from men’s?
They’re cut for a woman’s proportions, and sets like Merino.tech give you top and bottom in one buy. Fit matters most — snug, not tight — so choose the size that layers smoothly.
Can I wear cotton under my ski clothes?
No — "cotton kills." It soaks up sweat, goes cold and clammy, and won’t dry. Always choose merino or synthetic base layers.
Written by
Melissa
Melissa splits her year between Texas and Summit County, Colorado, where she has spent countless summers and winters hiking, skiing, fishing, and exploring the high country. She started Breckenmendations to help visitors make the most of Colorado's mountains with the gear, tips, and local know-how she wishes she'd had on her first trip up I-70.
Breckenmendations is written by locals who actually hike, ski, and explore Colorado — see how we pick what we recommend.