When temperatures drop, it’s time to layer up. To cut down on excessive and bulky layering, start with a base layer of warm long johns.
Also known as thermal or long underwear, long johns are two-piece garments — a top and a bottom — that you can wear together or separately, based on your needs. While all long johns have long sleeves and legs, their material and weight vary, and determine how warm and toasty they keep you.
In this article: Meriwool Men’s Base Layer Merino Wool Heavyweight Thermal Pants, Hocosa of Switzerland Women’s Long Underwear Pants and Merino.tech Merino Wool Base Layer Women’s Thermal Shirt.
Long johns are made of closely knit synthetic or natural fibers that retain heat. Because layering can make you sweat, especially if you’re going between outdoors and indoors, you want a pair that also offers breathability so you don’t overheat.
Long johns are made of thin fabric so you can comfortably wear them underneath pants and long-sleeved shirts. You can wear underwear and bras underneath them, as they aren’t meant to replace undergarments. You can also wear a tank top beneath a thermal top for extra warmth. The tops wear well under flannel shirts and wool sweaters and can provide a buffer from itchy outerwear.
If you’re skiing, hiking, hunting or camping in the winter, long-john bottoms are great under snow pants. For outdoor winter activities, choose long johns with an "athletic" or tighter fit, as well as moisture-wicking properties to reduce your risk of hypothermia as you sweat.
Thermal underwear is made from a variety of materials:
There are four common weights for long underwear:
Smartwool Men’s Merino 250 Baselayer Bottom
These high-end merino wool bottoms keep out the cold and are user-recommended for winter camping and backpacking. They wick away sweat and don’t cause chafing. The interlocking natural fibers offer thermoregulation and breathability.
Sold by Dick’s Sporting Goods
Meriwool Men’s Base Layer Merino Wool Heavyweight Thermal Pants
These heavyweight thermals have been worn by satisfied users in the Arctic Circle to keep them warm in subzero conditions. The 400-gram-per-square-meter merino wool blocks cold drafts while also letting your skin breathe.
Sold by Amazon
These midweight merino wool bottoms come with wool socks so that your lower half is covered. These long johns are versatile for indoor and outdoor use. They’re also available in light and heavy weights and are machine-washable.
Sold by Amazon
Hocosa of Switzerland Women’s Long Underwear Pants
With a lightweight blend of merino wool and silk, these bottoms feel luxurious on the skin and keep you just as warm as bulkier long johns. They wick away moisture and you can get away with not washing them for weeks.
Sold by Amazon
Merino.tech Merino Wool Base Layer Women’s Thermal Shirt
This midweight merino wool top comes with a pair of wool socks. The top is soft and available in 37 colors. It’s perfect to wear under a sweater or cardigan, but pretty enough to wear alone.
Sold by Amazon
Fruit of the Loom Men’s Classic Midweight Waffle Thermal Henley Top
This classic thermal top can be worn standalone or under your favorite flannel for milder days. The cotton-polyester blend fits close to the body and whisks moisture. It’s a good value and the waffle weave is attractive.
Sold by Amazon
TSLA Men’s Thermal Underwear Set
This affordable microfiber top and bottom are warm, soft and moisture-wicking. They keep you warm when the temperature drops below freezing and can be worn for sports. Be aware that they run small, so you might want to size up.
Sold by Amazon
This fleece-lined base layer can be worn as pajamas or under clothing outside in freezing weather. The fuzzy lining makes this set thick, but not too bulky. The material has some stretch, which makes the bottoms as comfy as leggings.
Sold by Amazon
Fruit of the Loom Women’s Micro Waffle Thermal Set
With the softness of cotton, these cotton-polyester long johns trap heat due to their synthetic fibers. The top and bottom work great as pajamas and the leopard print is fun for sleeping. The waffle weave is a winter classic look to wear on top and out of the house.
Sold by Amazon
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