10 Best Long Underwear For Cold Weather 2025 in the United States

The Cuddl Duds Thermal Underwear for Women is designed to keep you warm in cold weather with its brushed fleece lining and matte soft exterior. The heavy-weight material ensures good insulation, while the moisture-wicking fabric helps in keeping you dry by absorbing and evaporating sweat. The inclusion of spandex provides a comfortable stretch, ensuring a snug fit without restricting movement.

The set includes a top with thumbholes and modern rise leggings, both of which are designed to offer head-to-toe protection against the cold. Additionally, the fabric offers 50+ UV protection, making it a practical choice for outdoor activities. The design is sleek and versatile, allowing it to be worn as a base layer or on its own.

However, the thermal set might feel a bit bulky for some users who prefer ultra-lightweight options. Its durability is promising, thanks to the densely knit fabric, but long-term wear and tear are still to be tested. The material blend of 93% polyester and 7% spandex makes it easy to care for with a simple machine wash. This thermal set is ideal for women looking for effective cold-weather gear that combines comfort, warmth, and versatility.

The Merino.tech Merino Wool Base Layer Set is a solid option for anyone looking for comfortable and effective thermal underwear for cold weather. Made from 100% superfine merino wool, it offers a soft feel that won’t irritate the skin, which is a significant strength for daily wear. With a midweight of 250 g/m², it strikes a good balance between warmth and breathability, making it suitable for various outdoor activities, from hiking to simply lounging around in chilly conditions.

One of the standout features of this base layer is its moisture-wicking capability. Merino wool excels in managing moisture, allowing it to keep you dry and fresh even during physical activities. Additionally, its natural odor-resistant properties mean you can wear it for longer periods without worrying about unpleasant smells, which is ideal for active users.

There are a few drawbacks to consider. While the set is durable, proper care is essential; it requires hand washing and laying flat to dry to maintain its longevity. This might be inconvenient for some users who prefer machine wash-friendly options. Also, while the midweight fabric is versatile, individuals seeking ultra-heavyweight options for extremely cold conditions might find it less suitable. The added bonus of receiving Merino wool hiking socks with the set is a thoughtful touch, enhancing its value as a gift or personal purchase. This Merino wool thermal underwear set can meet the needs of outdoor enthusiasts or anyone needing extra warmth in cold weather with its blend of comfort, functionality, and quality.

The WEERTI Thermal Underwear for Men Long Johns with Fleece Lined is designed to offer excellent insulation and comfort during cold weather. Made from 92% polyester and 8% spandex, the material is lightweight yet effective at trapping body heat, making it ideal for layering under various outfits. The snug fit acts like a second skin, minimizing heat loss and providing a sense of security throughout winter.

The moisture-wicking properties of the fabric are impressive, keeping you dry by quickly absorbing and evaporating sweat, which is crucial for maintaining comfort during physical activities. Additionally, the 4-way stretch ensures flexibility and full range of motion, making it suitable for both active and casual wear. The seams are strong and durable, reducing the risk of premature tearing.

One potential drawback is the lack of specific mention of odor resistance, which might be a consideration for those looking for long-term wear without frequent washing. Another point to consider is the fit; while the snug design is excellent for heat retention, it may feel too tight for some individuals who prefer a looser fit. This thermal underwear is a solid choice for anyone needing reliable warmth and moisture management in cold weather, whether for outdoor activities or everyday wear.