When pursuing cold weather activities, layering your clothing isn’t just another style choice, it’s a necessity. Keeping warm and dry is paramount in damp and freezing conditions. When facing so many choices, determining the best option can be a daunting task. Below we offer some well thought out advice on choosing the perfect set of long underwear for the conditions you’ll be facing. This is followed by recommendations regarding available features, budget considerations, and garment uses.

Options to Consider when Choosing Long Underwear:

There are several options to focus on when shopping for long underwear bottoms. First and foremost is their fit. A snug fit is best for providing effective thermal protection. This is the primary purposes of good thermal underwear. By staying tight to the skin the underwear is able to maintain body heat, provide easy mobility without bunching and stay efficient at wicking off sweat. The second important aspect is weight. Long underwear is available in lightweight, mid-weight, and heavyweight styles. This choice is best made by taking into account the temperatures and activities you’ll be involved in.

Long Underwear is constructed from a variety of fabrics. Each type has its own benefits and drawbacks. Standard fabric options include synthetics, merino wool, and silk. Synthetics offer the greatest durability and a good choice when it comes to staying dry. They are a mid-level choice for odor control and are most effective when odor-fighting agents are added to the fabric. However, they fall behind where it comes to comfort and potential temperature control. Merino Wool is great for maintaining warmth and offers some cooling advantages when needed. It is naturally resistant to odors as well. Wool is not as durable as synthetic alternatives, however, and will not feel as dry. Silk is best suited for lighter activities. It offers the highest degree of comfortable and is good at wicking sweat. However, it falls short of other alternatives when it comes to durability and odor control.

Best Pick for Strenuous Activity:

Odlo Blackcomb Evolution Warm Base Layer Pants

This set of mid-weight long underwear is perfect for winter sports and other activities involving a lot of movement. You will experience easy motion with this pair, as they are virtually seamless as rotary knitting techniques are used in their manufacturing to eliminate the need for seams. They are made from a partially recycled synthetic fabric, a blend of polyamide, polyester and elastane and are treated with an antimicrobial to reduce odor. These bottoms also offer protection from ultraviolet rays with a UPF rating of 30. Integrated ventilation provides great breathability in all the important areas and they are moisture wicking and quick drying as well. This underwear makes for an equally great choice for spending the day whether you’re revving up the snowmobile or cruising down the slopes.

Best Pick for Extreme Cold:

Patagonia Capilene Thermal Weight Long-Underwear

When facing the most extreme cold temperatures, this set of heavyweight bottoms will keep you comfortable as well as warm. Created from a blend of recycled polyester and spandex, they offer a soft, stretchy material which provides a warm, moisture-wicking interior and a slick outer layer. The material is treated for long-lasting odor control. They are also constructed with a fully functional fly and flatlock seams for chafe-free wearing. As compared to other heavyweight options this undergarment provides great mobility and functionality and is the perfect pair to use when facing extreme conditions.

This garment headlines are list of the best thermal underwear, and for good reason.

Best Pick for Maximum Functionality:

Smartwool Merino 150 Long Underwear

For long underwear that is useful in many situations, look to Smartwool. Made from a blend of merino wool and nylon, these bottoms combine the best features of each material. The merino wool retains body heat, breathes, and naturally resists odors. The nylon core adds durability and functionality while keeping the comfortable wool next to your skin. Features of this underwear include a fully functional fly, mid-rise design and a wide, comfortable waistband. This pair of bottoms is great for hiking, mild winter sports or casual use on cold days.

Best Pick for Casual Comfort:

REI Co-op Silk Long Underwear

When seeking ultimate comfort from your bottom layer, this silk, lightweight underwear makes the cut. Their thin, flexible material is perfect for casual everyday use and wears pleasantly under jeans or slacks. They are also treated with a wicking enhancement to stay consistently dry. These bottoms feature a wide, comfortable waistband and rib-knit cuffs to ensure a balanced overall fit. This is a prime choice for anyone needing some day-to-day long underwear that is convenient and comfortable.

Best Pick for Affordability:

Patagonia Capilene Lightweight Long Underwear

For overall value, this lightweight long underwear offers the most bang for your buck. It is made from 100% recycled polyester, which is treated for permanent odor control. With a UPF rating of 35, ultraviolet rays will be no problem either. Sold at an affordable price, they still offer all the great features you’d expected from Patagonia. These include a functional fly, chafe-free seams, a smooth outer surface and a soft elastic waistband. High breathability, quick-drying material and the moisture-wicking design allows for use during strenuous activity as well as casual. As such, they are a great all-around choice for bottoms. You can find cheaper options, but none which offer so many benefits.