Base layers are an essential part of an outdoor clothing system since temperature and moisture management are key in conditions from blazing heat to blizzards. We’ve rigorously researched 30 sets and tested the eight most promising options side-by-side to put together this review of the best base layers available. After thousands of days and nights on trail, we know which ones are the warmest, lightest, most breathable, and comfortable for a wide range of temperatures.
To complete your winter layering system, be sure to dive in to our review of the best down jackets, fleeces, and winter coats for both men and women.
Quick Picks for Base Layers
Check out this quick list of the best base layers, or continue scrolling to see our full list of favorites with in-depth reviews.
Best base layer overall: Smartwool Classic Thermal Men’s ($120) / Women’s ($120)
Best lightweight wool base layer: Smartwool Classic All-Season Men’s ($90) / Women’s ($90)
Best synthetic base layer: Patagonia Capilene Midweight Men’s ($79) / Women’s ($79)
Best budget base layer: REI Midweight Half Zip Men’s ($60) / Women’s ($60)
Best sun shirt: Outdoor Research Echo Hoodie Men’s ($75) / Women’s ($75)
Warmest base layer: Odlo Blackcomb Eco w/Face Mask Men’s ($115) / Women’s ($115)
Most affordable base layer: Helly Hansen Lifa Stripe Men’s ($45) / Women’s ($45)
Best warm-weather base layer: Patagonia Capilene Cool Trail Men’s ($55) / Women’s ($55)
What’s new
Cold weather has kept us bundled in our favorite base layers and given us the chance to try on some new ones as well:
- The Smartwool Classic Thermal Men’s / Women’s is a great value for its warmth in wet conditions and odor-resistance.
Smartwool Classic Thermal
Best wool base layer overall
Price: $120
Weight: (Men’s M): 10.3 oz.
Fabric/Weight: Midweight merino wool
Pros
- Good value
- Excellent mositure wicking
- Warm when wet
- Breathable
- Odor-resistant
- Stylish enough to be worn on its own (250)
Cons
- Can pill after washing
- May hold onto lint & pet hair
- Not as durable as synthetics in the long run
Smartwool’s Classic Thermal Merino (men’s / women’s) does an excellent job of holding in heat and wicking away moisture. And since it’s wool, it doesn’t hold on to odors which is a real plus on multi-day trips.
The Thermal is just the right thickness to help you thermoregulate in chilly fall and winter conditions. It’s available in a variety of styles, but we like the quarter-zip version best for neck and chest ventilation. The Classic Thermal is high-quality and performs well, which has made it our go-to base layer for a long time.
Smartwool Classic All-Season
Best lightweight wool base layer
Price: $90
Weight: (Men’s M): 6.5 oz.
Fabric/Weight: Lightweight merino wool + nylon
Pros
- Super soft wool blend
- Low-profile seams reduce rubbing
- Warm when wet
- Odor-resistant
- Lays flat
Cons
- Thin material doesn't last as long
- Light colorways can be semi-transparent
The Smartwool Classic All-Season (men’s / women’s) is one of our favorite multi-purpose tops. It has a super soft 88% merino / 12% nylon blend that feels comfortable against bare skin. We found it is the right thermal weight for most summer camping trips; thin and breathable enough when the sun is out but also a cozy base layer for cool nights in the 50s. We love the low-profile seams that really help minimize chaffing, especially with a backpack on. Though the thin material is a little less durable in the long run, and some of the lighter women’s colors are semi-see through, this is still an excellent option for cool (but not cold) summer backpacking trips.
Patagonia Capilene Midweight Crew
Best synthetic base layer
Price: $79
Weight: (Men’s M): 6.2 oz.
Fabric/Weight: Midweight polyester
Pros
- Affordable
- Durable
- Very comfortable
- Excellent moisture wicking
- Easy to layer
Cons
- Not as warm or odor resistant as wool
The Patagonia Capilene Midweight (men’s / women’s) is a durable and comfortable base layer top that’s quite the steal at its price point. We’ve used this top for multiple thru-hikes, and it’s still going strong nearly a decade later.
Of all the synthetic materials we’ve used, Patagonia’s proprietary Capilene blend is the softest, stretchiest, and the best at wicking moisture. While it doesn’t trap heat quite as efficiently as some wool base layers, the Capilene Midweight top is still highly versatile and easy to layer.
During shoulder seasons, we often hike in this shirt by itself since it’s breathable and provides just the right amount of insulation for temperatures above freezing
REI Midweight Half Zip
Best budget base layer
Price: $60
Weight: (Men’s M): 9.8 oz.
Fabric/Weight: Midweight polyester
Pros
- Affordable
- Durable
- Warm
- Very comfortable
- Excellent moisture wicking
- Easy to layer
- Thumbholes
Cons
- Not as odor resistant as wool
- Heavier than most
Sometimes you come across a budget option that performs just as well as higher end items, and that is certainly the case with REI’s Midweight Half Zip top (men’s / women’s). This base layer is warm, durable, and comfy against the skin, so it’s become a staple in our layering system.
The zipper allows you some control over your level of insulation, so it’s versatile for a good range of conditions. Since it’s on the heavy side compared to others, we tend to only take it out in colder temperatures when we know we’ll be wearing it for most of our time outside. That said, the weight is still reasonable for packing it as a just-in-case item if you’re the type that likes to have an extra layer for sleeping in on chilly nights.
This top is durable enough for many seasons of use, making the already small price tag even more appealing. If you’re in need of something warm and well built on a budget, this is your guy.
Outdoor Research Echo Hoodie
Best sun shirt overall
Price: $75
Weight: 5.2 oz.
UPF Rating: 15
Pros
- Ultralight
- Great value
- Breathable
- Full coverage
- Very comfortable
- Inclusive sizing men’s / women’s)
Cons
- Not as durable
- Holds odor
- Lower UPF rating than others
The Outdoor Research Echo Hoodie (men’s / women’s) has been our go-to sun shirt for years since it’s ultralight, highly breathable, and incredibly comfortable. The hood and thumbholes provide ample coverage, while the fabric – quite frankly – feels like you’re wearing nothing at all. The light fabric sacrifices a bit of durability to remain cool and breathable, so you’ll want to treat it with care to make sure it lasts for years. That said, we’ve worn ours extensively without issues and think it’s an awesome choice for those who prioritize comfort above all else.
Odlo Blackcomb Eco w/ Facemask
Warmest base layer
Price: $115
Weight: (Men’s M): 9.5 oz.
Fabric/Weight: Polyester
Pros
- Very Warm
- Built-in face mask
- Durable
- Odor-resistant
- Easy to layer
Cons
- Not as versatile
- Heavier than others
- Tight fit may not appeal to some
Odlo’s Blackcomb Eco w/Face Mask (men’s / women’s) is uniquely designed with a balaclava-style hood to keep you warm and protected in the coldest conditions. The slim fit and seamless design of this top make it easy to layer and especially comfortable when worn under a backpack. The polyester blend offers excellent breathability and odor control, so you can wear this layer for multiple days between washes. Because the Blackcomb is so warm, it’s not quite as versatile as many of the other shirts on our list, but when it’s cold out it’s pretty hard to beat.
Helly Hansen Lifa Stripe Crew
Most affordable base layer
Price: $45
Weight: (Men’s M): 4.8 oz.
Fabric/Weight: Lightweight polypropylene
Pros
- Affordable
- Quick-drying
- Excellent moisture wicking
- Easy to layer
- Breathable
Cons
- Not as versatile as some others
- Not as warm as others
If you’re on a budget, the Helly Hansen Lifa Stripe Crew (men’s / women’s) is an affordable option that doesn’t skimp on performance. Helly Hansen’s proprietary Lifa Dry material excels at moisture wicking and dries very quickly, so it’s a great choice for high-output activities. This base layer isn’t as warm as some others on our list, but the fit and flatlock seams make it comfortable for layering under other clothing. It’s also designed with flat, fitted cuffs that work nicely under gloves. We love the Lifa Crew for snowsports and backpacking since it has just the right amount of insulation for active days.
Patagonia Capilene Cool Trail
Best warm-weather base layer
Price: $55
Weight: (Men’s M): 5.5 oz.
Fabric/Weight: Ultralight polyester
Pros
- Affordable
- Soft
- Highly breathable
- Quick-drying
- Excellent moisture wicking
Cons
- Not as odor resistant as wool
- Not insulative
Base layers aren’t just for keeping you warm; the Patagonia Capilene Cool Trail (men’s / women’s) actively helps cool you down. The material is highly breathable and evaporates moisture fast, so it’s perfect for vigorous hikes and warm, sunny conditions. This shirt feels like cotton, so it’s excellent for those with sensitive skin. But it performs like polyester to meet the demands of high-output outdoor activities.
Best Base Layer Bottoms
Best base layer bottoms overall
- Patagonia Capilene Midweight Men’s / Women’s – We’ve had the same pair of Patagonia’s Capilene Midweights for years, and they’re showing very few signs of wear. We find the level of warmth they provide to be appropriate for most of the year, and their athletic fit makes them easy to layer.
Best warm base layer bottoms
- Smartwool Classic Thermal Merino Men’s / Women’s – These bottoms are our go-tos for winter and high-alpine adventures when temperatures dip to freezing and below. They’re the most heat efficient bottoms on our list, and they’re the best at repelling odor after multiple days of wear on the trail.
Very comfortable & warm base layer bottoms
- Odlo Performance Wool Warm Men’s / Women’s – These are some of the best warm base layer bottoms for backpacking. They’re very form-fitting and the waistband lays super flat, so they’re very comfortable for layering and under backpack hip belts.
Best budget base layer bottoms
- REI Midweight Men’s / Women’s – If you’re on a budget, REI’s Midweight bottoms are a great choice. They have a flat waistband that lays comfortably under hiking pants and hip belts. These synthetic layers will keep you warm down to around freezing, so they’re good for backpacking in shoulder seasons.
What’s Most Important to You in a Base Layer?
PRICE
You don’t have to spend a ton of money to get a great base layer, but warmer, thicker layers and those made with natural fibers do tend to cost more. With that in mind, we’ve identified some quality options at each price point that provide good value.
Best mid-range base layers
- Patagonia Capilene Midweight Men’s / Women’s
- Smartwool Classic All-Season Men’s / Women’s
- Outdoor Research Echo Hoodie Men’s / Women’s
Best budget base layers
- Helly Hansen Lifa Stripe Men’s / Women’s
- REI Midweight Half Zip Men’s / Women’s
- Patagonia Capilene Cool Trail Men’s / Women’s
Best high-end base layers
WARMTH
A quality base layer provides insulation, trapping body heat to keep you warm in varying outdoor conditions. When hiking, especially in colder climates or unpredictable weather, maintaining a comfortable body temperature is essential. However, it’s also important to have effective layers for cool and warm weather days. Be sure to select layers that have an appropriate level of insulation for the types of weather you’ll actually encounter.
Warmest base layers
- Smartwool Classic Thermal Men’s / Women’s
- Patagonia Capilene Midweight Men’s / Women’s
- REI Midweight Half Zip Men’s / Women’s
- Odlo Blackcomb Eco w/Face Mask Men’s / Women’s
Best base layers for temperatures above freezing
Best base layers for sun protection/warm weather
WEIGHT
For most 3-season trips, we prefer lightweight base layers because they’re more comfortable to wear under other clothing. Lightweight layers also help keep weight low for backpacking trips, when you’ll be carrying them in your pack for most of the day to wear in camp at night. Having said that, always make sure you have the right gear, which can be very different from light gear.
Best ultralight base layers
Best lightweight base layers
- Smartwool Classic All-Season Men’s / Women’s
- Patagonia Capilene Midweight Men’s / Women’s
- Patagonia Capilene Cool Trail Men’s / Women’s
Best heavy-duty base layers
MATERIAL
All of the base layers we recommend are breathable, moisture-wicking, and quick-drying, but each material excels in a slightly different way. Wool is great for thermoregulation, breathability, and odor control. Synthetics aren’t as warm, but they dry quickly and tend to be a bit more durable and affordable. Silk base layers are super comfy against the skin but will absorb more moisture than others and are best used as sleep or in-camp clothes that you won’t sweat in as much.
Best wool base layers
- Smartwool Classic Thermal Men’s / Women’s
- Smartwool Classic All-Season Men’s / Women’s
- Icebreaker 200 Oasis Men’s / Women’s
Best synthetic base layers
INCLUSIVE SIZING
Everyone should have high performance options that make them feel great and look great. After all, the outdoors is for everyone!
Base layers with inclusive sizing
- Patagonia Capilene Midweight Men’s / Women’s
- REI Midweight Half Zip Men’s / Women’s
- Outdoor Research Echo Hoodie Men’s / Women’s
- Patagonia Capilene Cool Trail Men’s / Women’s
BASE LAYER BOTTOMS
Though we have primarily focused on base layer tops, your lower half can benefit from some additional coverage too. A pair of base layer bottoms is also an essential part of any outdoor clothing system.
Best base layers bottoms
Critical Base Layer Considerations
MATERIAL
The material a base layer is made from can be a good indicator of how it will perform in various conditions. Below we’ll detail some pros and cons of the most common base layer materials.
- Wool – Wool tends to be more expensive than synthetic base layers, but it also has the best balance of heat efficiency, odor control, and moisture wicking capability. Most modern wool base layers are also actually quite soft and comfortable against bare skin. Wool layers may not last as long as synthetic ones and they tend to pill after washing and hold onto lint and pet hair. That said, if you use our technical fabric care tips below, you should still get plenty of use out of your wool clothing.
- Polyester – Polyester clothing is durable, quick-drying, and typically lighter weight than wool. We love synthetic shirts for their excellent moisture wicking capabilities and often slightly more accessible price point. Synthetic layers don’t insulate as well as wool and they can actually sap a lot of your heat if they get wet. Still, they’re much easier to care for and shouldn’t need to be replaced for many years.
- Silk – Silk is highly packable and has an excellent warmth-to-weight ratio. This ultralight material dries quickly and is very durable for the weight, but it does require extra special care to maintain. Because of the delicate nature of this material, we tend to use silk base layers for sleep clothes rather than on the trail. The soft texture is super comfy and a great option for anyone with sensitive skin. Though it’s not as effective at insulating when wet, we like to wear silk base layers inside our sleeping bag to protect them from sweat and trail grime.
TIPS FOR LAYERING
Finding the perfect outdoor clothing layering system ultimately comes down to personal preference and the conditions you’re in. Check out our Hiking Clothing 101 article for some great tips to help find what works for you.
CARING FOR TECHNICAL FABRICS
Technical fabrics require a little special care to keep them performing their best. Always follow the washing directions on the tags carefully, but here are some good guidelines:
- Use a front loading washer – The agitator in a top loading washer can snag zippers or drawstrings and can be hard on delicate fabrics and seams. Make sure you zip all the zippers and tie the drawstrings before washing to prevent wear and tear.
- Use a technical fabric wash – We recommend Nikwax Tech Wash or Woolite for washing any technical fabrics because these solutions won’t leave fragrances or residue on your clothing.
- Only wash when you really need to – A lot of technical fabrics are designed to be antimicrobial and shouldn’t hold odors. Hiking clothing doesn’t necessarily need to be washed after every use.
- Don’t use fabric softener or dryer sheets – Fabric softener and dryer sheets can leave behind residue on the fabric and negatively affect performance by reducing breathability and insulation quality.
- Hang dry when possible – Heat and agitation in the dryer can damage technical fabrics so it’s best to lay them flat or hang them on a line to dry naturally.
Honorable Mentions
These base layers are also some of our favorites and one of them could be just right for you:
- Icebreaker 200 Oasis Crewe (men’s / women’s) – This high-quality wool top is very similar to our top pick, Smartwool Classic Thermal, but it’s slightly less breathable which gave the edge to Smartwool. That said, the Oasis Crewe is a bit softer against the skin so we still think it’s a great choice for low-output activities when you’re not at risk of overheating.
- Ortovox 185 Rock N Wool (men’s / women’s) – This wool top features a stylish design and feels softer than other wool base layers, but we found the seam at the elbows to be irritating after prolonged wear.
