Whether you’re working outdoors, braving the early morning chill, camping in remote areas or going skiing on a sunny day, a good pair of thermal underwear will keep you warm. I live in Wisconsin, where winter temperatures can drop to extreme lows, so having a sturdy pair of thermal underwear is crucial, especially since I spend most of my time outdoors. While some options are rated for different temperatures and activities, the best men’s thermal underwear should keep you warm and dry in all conditions.
Ridge Merino Aspect Medium Fleece Bottom Long Sleeve Shirt
The Ridge Merino Aspect Medium Weight Wool Bottom Long Sleeve Shirt is a technical shirt that doesn’t look too technical. This shirt is both heavyweight and fitted, making it attractive on its own or worn as a baselayer. It’s easy to have a closet full of expensive technical shirts that you don’t wear because they don’t match or aren’t made well enough. If you run into this problem often, this t-shirt may be a solution.
The Ridge Merino Aspect comes in a neutral color that helps match a variety of outfits. It also has thumbholes to hold it in place when you put a sweater on. But that’s the extent of this t-shirt’s outdoor look; those thumbholes disappear into the cuffs, so they’re unobtrusive if you don’t want them there. All of this makes the shirt look less technical and more versatile.
The t-shirt is made from a wool blend: the blend is 84% merino wool and 16% nylon. The nylon adds some stretch and durability, so the Ridge Merino Aspect is more durable than one made of pure wool. The wool thread is very fine – 18.5 microns – and the small diameter of the fibers prevents modern wool shirts from being scuffed.
Other tiny details make this t-shirt comfortable and easy to wear. There is no label, and the shoulder seams are offset with slit sleeves. This cut allows unrestricted arm movement and the seams are not above the shoulders, thus preventing scuffing under the backpack straps. The torso is cut long so your lower back stays covered. Overall, this shirt fits well but is not tight. So you can wear it on its own, but if you wear it under a sweatshirt, it won’t look bulky.
Finally, this t-shirt has a UPF 50+ sun protection rating, which means the fabric is tightly woven enough that less than 2% of UV rays can pass through. Sun protection is doubly important if you’re on snow or water, where the light will either reflect off the ground and back, or be less protected from the atmosphere. Outdoor clothing that combines sun protection will protect you from energy expenditure and skin damage burns.
Men’s Recycled Premium Waffle Pants
You know what’s better than waffle pants? Three pairs of waffle pants. This multi-pack from Fruit of the Loom allows you to cycle through thermal underwear for multiple days – great if you wear them to work or just want to wait longer to do laundry.
Smartwool Classic Thermal Merino Wool Bottoms
We love the Smartwool Classic Thermal Merino Bottom and give it our highest honor. When the temperature really drops, the combination of warmth and comfort in these fall pants is outstanding. The special interlock knit provides excellent breathability, especially considering the thick 250 g/m2 cut of 100% merino wool. You’ll find that the back lining matches the front for improved comfort and fit. The extra-wide wool-lined waistband and full flatlock seams reduce any common itchy complaints. While these are designed for cold conditions, their balance of warmth and breathability allows them to serve multiple purposes even when temperatures start to warm up.
Regardless of the thick construction of this pair of bottoms – in fact, it’s one of the most durable all-natural layers we’ve tested – all merino layers require some level of care beyond that of most garments.Classic Thermal tend to stretch with regular use between washes, but don’t try to throw them in the dryer to shrink them. Careful washing, mainly flat or air dry, will help extend the life of this and all merino baselayers. While washing can be annoying, the excellent temperature regulation makes this long undershirt worth the extra effort, especially for those who work or play in very cold conditions.
Carhartt Force Midweight Micro-Mesh Bottom Shirt on
There’s a lot to love about these affordable thermal garments from workwear brand Carhartt: they’re lightweight, wick away sweat, keep you warm and don’t have a lot of extra stuff to wear. We’re also impressed with extras like thumb loops on the sleeves, anti-odor properties, scuff-resistant seams, and even tagless labels on the pants for added comfort. But what are their most desirable qualities? They keep you from freezing or overheating in all types of weather, activities and areas.
“These are very warm,” said our tester. “In 30-degree weather, I was able to use the heat and a shell for snowboarding. The tops were also warmer than a t-shirt and hoodie combo on a walk in a windy backyard on a cool California evening. I have a lot of expensive baselayers and these are as warm as most, if not warmer.”
Warmknit Long Thermal Underwear
The Mack Weldon exclusive Warmknit is a return to the classic waffle-knit thermal underwear, but with modern fabrics to improve comfort and warmth. It combines a micro waffle knit pattern with Thermolite for improved warmth and breathability, which Mack Wheldon blends with modal and spandex; the modal keeps the pair lightweight, while the spandex provides stretch for unrestricted movement. The micro waffle knit fabric is soft to the touch.
Customers report that these are very warm and the sizing is true to size. The elastic waistband doesn’t sag or droop throughout the day, and the ankles stay in place thanks to the cuffed hem. They were also pleased with how the Warmknit performed after multiple washes and wears.
