10 Best Thermals For Women 2026 in the United States

The Cuddl Duds Thermal Underwear for Women is a comfortable and practical option for cold weather. Made with 93% polyester and 7% spandex, the material is designed to be both warm and stretchy. The brushed fleece lining adds an extra layer of warmth, making it ideal for chilly conditions. The moisture-wicking fabric helps keep you dry by absorbing and evaporating moisture, which is a valuable feature for active wear or extended use. Additionally, the odor resistance feature ensures you stay fresh even after prolonged wear.

The spandex stretch provides a snug fit, which is complemented by the thumbhole sleeve top and modern rise leggings for a streamlined look. The set also offers 50+ UV protection, making it useful for outdoor activities. The seam construction is designed to be durable and comfortable, minimizing chafing and irritation.

However, the heavyweight nature of the fabric means it might not be suitable for milder climates or indoor activities where lighter thermals would be preferable. The bulkiness could also be a downside for those looking for a more discreet base layer. This thermal set is best suited for women looking for robust cold-weather protection, whether for outdoor adventures or simply staying cozy indoors.

The Merino.tech Merino Wool Base Layer Women Set stands out in the thermals-for-women category for its use of high-quality merino wool, which offers excellent moisture-wicking properties and odor resistance. With a weight of 250 g/m², this midweight option strikes a balance between warmth and comfort, making it suitable for various activities, from hiking to lounging at home. The fabric is soft and designed to prevent itching, ensuring all-day wearability without discomfort.

One of the key strengths of this thermal set is its breathability, which allows for temperature regulation, keeping you comfortable throughout the year. Additionally, the inclusion of merino wool hiking socks adds value to the package, making it a thoughtful gift option for outdoor enthusiasts.

There are a few considerations to keep in mind. The maintenance requires hand washing and air drying, which can be inconvenient for some users accustomed to machine washing. Also, while the midweight design provides good thermal insulation, it may not be warm enough for very cold climates, where a heavyweight option might be preferable. The product is imported from China, which may raise concerns for those prioritizing locally made items. Despite these minor drawbacks, the Merino.tech set is a strong contender for anyone looking for effective, stylish thermal underwear that meets the demands of an active lifestyle while ensuring comfort and performance.

The Smartwool Women's Standard Classic Thermal Merino Base Layer Crew in Chalk Violet Heather is a strong choice for women seeking reliable thermals. Made from 100% Merino wool with interlock knit, it offers excellent comfort, breathability, and thermoregulation, making it suitable for activities like snow skiing, hiking, and mountaineering. Its slim fit is designed to contour to the body, providing a flattering silhouette, while the back body seam that wraps to the front and raglan sleeves enhance mobility.

The flatlock seam construction is particularly beneficial as it helps minimize chafing, a common issue with thermal wear. Additionally, the fabric's natural odor resistance and moisture-wicking properties ensure you stay fresh and dry during intense activities. However, some users might find the wool material a bit heavier compared to synthetic alternatives, which could impact the weight of their gear. Furthermore, the slim fit may not appeal to everyone, particularly those who prefer a more relaxed fit.

Despite these minor drawbacks, this thermal base layer is well-regarded for its performance and comfort.