To test the Patagonia Capilene Midweight, I wore this base layer against the skin during an October trail running traverse of the Wasatch range. The temperatures ranged from highs in the 70s to lows in the high 30s. I wore just the Capilene Midweight from 6 am to 8 pm when I added a Patagonia Houdini wind shirt to ward off the cold. That was perfect until 3 or 4 am when I added a fleece on top of that.

These types of questions will help guide you in the direction of what holds more importance for you as a buyer. Decide which metrics are most important for your sport or activity—whether that's ice climbing or shoveling snow in your driveway—and base your decisions on those factors first. What we liked: Versatility, durability, most inclusive sizing, looks good on most people, color and pattern availability, reasonably priced Our base layers testing used six rating metrics with the following weightings to the overall final score:

WINTER BASE LAYERS

In short, they’re key if you want to focus more on your training and less on how you’re going to avoid frostbite on your next Spartan. What To Consider When Buying Base Layers Some base layer brands understand that people of all sizes love getting outside. Some brands still have yet to get the memo. Smartwool and Patagonia have the broadest range of sizes available, including plus sizes and kids’ sizes. Do you want base layers tight or loose? I am now the biggest base layer for kids convert, and I’m baffled on why it has taken me so long to invest in quality base layers for my kids.

Both Merino wool and synthetic base layers stand out in certain areas and most of us have a mix of synthetic and Merino base layers. It all comes down to personal preference and what kind of material is best for the activities you are doing. Best Base Layers for Babies While we may love the fabric of a base layer top, if the base layer bottom doesn't fit right, it won't feel comfortable. Worse yet, with a merino base layer bottom, we've sometime seen the same fabric we love for a top not have enough stretch for a bottom…and to develop holes in unfortunate areas. So, if you’re partial to an al fresco workout, we think buying a base layer is a no-brainer. That’s why we’ve tested some of the best money can buy to bring you our top recommendations. What is a base layer? Even if your base layers are designed for the regular laundry cycle, Helly Hansen suggests that “standard laundry detergent can leave behind a film that attracts odor-causing bacteria”-something to consider if your base layers see heavy use. What we love about Ellas wool is that the merino wool is super soft and warm. They claim to be buttery soft, and I can vouch for how warm and cozy they are.Let’s be honest, we all fared perfectly well without them before (Image credit: Susumu Yoshioka) 5. Sun protection Synthetic base layers tend to be a little more durable in the wash. They will require more frequent washing than your Merino layers, likely after every sweaty use, might get 2 wears out of an item if not sweaty. Nixwax Basewash is a great way to keep those base layers clean. A lot of detergents can leave residue behind that hang on to odors. Base wash helps clean and deodorize synthetic base layers. Ibex has long been a favorite of several testers, and the Ibex Journey, long sleeve crew base layer, did not disappoint. The Journey is a basic, lightweight baselayer made with merino wool and nylon blended fabric. The merino wool provides odor protection, while the nylon provides durability and less itch. However, we found that it still had some itchiness, surprising because our previous Ibex baselayers had zero itch. Liz Thomas edited this article and is a former Fastest Known Time (FKT) record holder on the Appalachian Trail, she has also hiked the PCT and CDT and is a Triple Crowner, in addition to having thru-hiked 20 other long trails.

Thumb holes prevent my hands and wrists from feeling the chill without having to layer up with running gloves (Image credit: Julia Clarke) 2. Keeping cool Ella’s wool is a company based out of Brooklyn, NY. Becca’s Norwegian roots were her inspiration to start the company when she couldn’t stand to see empty playgrounds in the winter after moving to New York.

Not really. I know I’ve mentioned a few good benefits of thumb holes in your outdoor gear, but let’s be honest, we all fared perfectly well without them before. You can always keep your hands warm on a run or a hike with gloves, and though I’ve heard runners say they like thumb holes because it stops their sleeves from riding up, I can’t personally say that’s ever a problem I’ve encountered. Maybe I don’t run swiftly enough? The teens favorite base layers are cheap ones I got from the REI brand on clearance. TMM Team Member Rita

Of all the synthetic blend options available Shred Dog’s foundation kids base layer seem to be the most loved by the team for the older kids. Their foundation base layer top and bottom come in sizes small to extra large. I grabbed Helly Hansen kids wool base layers on sale and they are the ones my daughter reaches for first. TMM Team Member Anna REI Base Layers for TeensThe final brand loved by tweens and teens among our group are the REI Co-op Long Underwear Tops/Bottoms.