We're convinced that by the time you pull your arms through the sleeves of this base layer and it hugs you like your favorite granny on Christmas morning, you'll feel the same level of love and affection we do for it. A super comfortable, soft, cush fabric combined with its superior ability to perform well in almost every environment and activity make this top a back-to-back-to-back award winner and a favorite among staff and testers.
SmartWool Merino 250 Crew Fit. Long arms and torso with a slightly looser fit throughout.
At 250 g/m², this top is the thickest weight merino wool fabric offered by SmartWool as well as in our testing. So it's not surprising that this is the warmest top that we tested. What makes this base layer so impressive is its versatility. It is a great layer in bitterly cold conditions but performs fantastically in warmer weather as well. This is the layer you can take with you heli-skiing in Alaska or fall hiking in Peru (and tons of applications in-between). Thick enough to be comfortably worn next-to-skin or as a mid layer increases its versatility.
During a day of fall climbing in Eldorado Canyon, this layer kept us comfortable as a stand-alone layer starting in the predawn light at 38 degrees and climbing through the 70-degree midday heat. We were blown away at its ability to keep us dry and both warm and cool as needed throughout the day. We praise its ability to serve you well through Spring, Fall, and Winter, but if you need a base layer for Summer ventures, we suggest a lighter option like the Patagonia Capilene Lightweight Crew.
Making our way to the summit of Mt. Hood. Frigid, whipping winds were no match for the SmartWool Merino 250 as our base.
Overall, this was the warmest layer we tested. We love it for its ability to keep you warm in the coldest conditions but also be useful across seasons without overheating or causing us to sweat out gallons of precious hydration.
Taking a breather from the lung bursting skinning in frigid dawn temps.
This baselayer earns top marks because even though it bats for the big leagues regarding warmth, it does an excellent job, for its weight, at breathing. It can keep you warm in the deep recesses of winter but when things heat up, this top kicks into high gear pulling sweat away from your skin, passing it through the fabric, and evaporating it at the surface. That means it works great for freezing cold resort days just as well as backcountry skinning ventures and hut trips.
It is not the most breathable top we tested, but all of the layers that score higher in breathability are not as warm, except the Patagonia Capilene Air, which is a close contender with the SmartWool. Its balance of warmth and breathability are what makes this a stand-out baselayer.
The SmartWool Merino 250 shining in its versatility across temperature ranges. Keeping us comfortable even when we're working up a sweat in warm fall temps in Eldo Canyon
Comfort and Fit
Right out of the gate, the drool-worthy comfort of the SmartWool Merino 250 stands out among other base layers and is one of its most shining and obvious attributes. The soft, thick, plush merino wool wraps around you like your favorite blanky as a child. It is a layer you never want to take off. You'll find yourself wearing it on the mountain, around the house, to the grocery store, out to dinner, to bed, etc.
A simple construction utilizes flatlock seams so that when worn, you can't feel the seam lines against your skin. Thoughtful offset shoulder seams keep your shoulders free for comfort while wearing a pack. A long torso and arms, combined with a stretch weave, allow it to be extremely mobile, moving with you and staying tucked in or keeping it in place when bending over or reaching up. It's one of the only models that doesn't incorporate a gusseted sewing pattern in the underarm, but we found that this exception doesn't affect its ability to move with you and stay in place.
The offset flatlock seam design makes for comfortable next-to-skin feel and keeps seems off the shoulder for carrying a backpack.
The overall fit runs a tad on the large side for a base layer. At 6ft, 150 lbs. A Medium is loose and fits better as a mid layer. If you want this to fit tightly next-to-skin or are in between sizes you may think about sizing down. We did notice that after a day of climbing with the sleeves pulled up on our forearms, they were loose and stretched out until it was washed and dried again. Overall, a simple design made of quality materials - nothing fancy here, just a fantastically cozy base layer.
The looser fit apparent in this photo. It did shrink up just a tad with some washes, but it's not a skin-hugging top if you're a thinner build.
After soaking this top in our timed drying speed test, the Merino 250 proved to not be the fastest at drying out. Being on the thicker side of the fabrics tested, we weren't necessarily surprised by this result. That said, it's not the slowest and even dried quicker than products with thinner fabric. And although it was slow to dry after being completely soaked thru, this top does a great job of wicking sweat and staying dry when being worn. It will just take a long time to dry when you jump in that alpine lake with it on. Being made of wool, this top still insulates when wet, it just doesn't feel all that nice.
This top's resistance to absorbing moisture did impress us. We had to agitate the fabric underwater, as with the other merino wool tops, in order to fully saturate this top. It's a common claim that merino wool can take on a significant amount of moisture before feeling wet, and our tests results echoed this claim.
Merino wool is unmatched in its warmth, breathability, and abilities to regulate temperature, wick sweat, stay dry, and resist odor. But the Achilles heel of merino is its lack of durability. The Merino 250 is going to be significantly more durable than most merino layers we tested due solely to the fact that it's a thicker fabric. The construction of this piece is extremely high quality, incorporating heavier-duty stitching in high wear areas. In our abrasion test, the SmartWool showed only signs of wear on the surface where other layers now sport a hole in the fabric.
While general wear and tear are inevitable, washing and drying a garment, especially merino wool, are going to be the real death of a garment. Merino wool is naturally anti-bacterial and incredibly resistant to odors. This means that you can wear this top more and wash it less, therefore extending the life of the garment while not upsetting the nostrils of friends and loved ones.
The Smartwool Merino 250 cuffs stretched out thru a day of climbing wearing them pulled up on our forearms. This stretch stayed until we washed and dried it again.
Although SmartWool claims this product is dryer-safe on a low setting, we suggest flat drying all merino wool products. As these products aren't the most rugged, the dryer will be your fastest route to base layer destruction.
Layering with this layer is fantastic. Worn over a short sleeve tee or a thin base layer, or under an insulated jacket or mid-layer, it remains comfortable and doesn't restrict movement.
For as thick as this fabric is, it layers smoothly and doesn't feel bulky or restrictive underneath an insulating layer. The elasticity of the weave allows it to hug you through movements and resist bunching when worn under a sticky mid layer. Its looser fit compliments it being worn over a t-shirt or another base layer and its handsome look allows for it to be worn out.
If you want a top that can easily be worn as a base layer against skin or as a mid layer, we suggest either the Smartwool 250 Merino or the Patagonia Capilene Air.
Outside of the heat of summer, this top is versatile across seasons. It's created to be a champion of warmth in the coldest settings, but because it does so well breathing and with thermo-regulation, it is equally functional (and fashionable) at a dinner party as at an unplanned bivy.
The SmartWool Merino 250 excelling in cold temperatures. It's one of the warmest layers we tested and the Editors' Choice for the Best Overall base layer.
We suggest using it for the coldest reaches of the year but feel comfortable wearing it for fall hikes, chilly climbing days, spring camping, and cozy movie nights. It's also a great international travel companion as you don't have to worry about washing it often, and it's versatile in both function and fashion.
At a nice rest belay ledge at last. The SmartWool Merino 250 flaunting its versatility through a full day of climbing in a wide range of temperatures and keeping us comfortable for the entire ride.
We're not going to pull the wool over your eyes on the price. It's not the cheapest option, but we feel the versatile performance and quality of fabric and construction justify the high cost. Remember that for outdoor adventures, one base layer is sufficient. If you treat it well and don't over-wash it, this top could be your sidekick far into the future.
The Merino 250 gives us everything we want in a base layer.
There are a lot of great base layers out there but we tapped this one for our Editors' Choice Award because of the impressive melding of all the qualities we want in a base layer rolled into one good-looking package. Warmth, breathability, comfort, and versatility live harmoniously under one roof in this top. We tested other outstanding tops and ones that score higher in specific qualities, which may work better for specific activities or seasons. But for an all-around, do-everything layer that you can throw on for almost every outing Fall through Spring, we recommend this one.