10 Best Base Layer Women Cold Weather 2025 in the United States

The Cuddl Duds Thermal Underwear set for women is designed to provide warmth and comfort during cold weather. The material, made with 93% polyester and 7% spandex, offers a good balance between warmth and flexibility. The fleece lining ensures the set is cozy, while the spandex stretch allows for ease of movement—a necessity if you're active outdoors. Additionally, the material's moisture-wicking properties help keep you dry by absorbing and evaporating sweat, which is crucial for maintaining body heat during cold conditions.

A significant strength is the UV protection feature, offering 50+ protection, which is beneficial if you're wearing it as an outer layer on sunny winter days. The design includes a thumbhole sleeve top and modern rise leggings, making it stylish enough to wear on its own for casual outings, as well as a functional base layer. The set's capability to be machine washed adds convenience to its care routine.

This thermal set is ideal for those who prioritize warmth, functionality, and style in cold weather, and it serves well as either a base layer or standalone piece.

The WEERTI Thermal Underwear for Women is designed as a cozy and flexible base layer for cold weather. Made from a blend of 92% soft polyester and 8% spandex with a fleece lining, it offers warmth without feeling heavy. The fleece inside adds extra insulation, which helps trap your body heat to keep you comfortable during chilly days. The fabric features strong moisture-wicking abilities, pulling sweat away quickly so you stay dry rather than damp, which is important for both comfort and warmth.

Its four-way stretch fit hugs your body snugly without restricting movement, making it easy to wear under other clothing or even as pajamas. The slim, tailored fit reduces bunching and heat loss while being gentle on the skin, minimizing irritation. This thermal set works best for women looking for a lightweight but warm base layer to wear under casual or formal clothes in cold climates.

The Merino.tech Merino Wool Base Layer Women Set is a solid choice for those seeking warmth and comfort in cold-weather conditions. Made from 100% superfine merino wool, this set offers a soft feel against the skin and minimizes itchiness, making it suitable for daily wear without discomfort. The material is naturally moisture-wicking and odor-resistant, helping to keep you dry and fresh throughout the day. This can be particularly beneficial for outdoor activities like hiking, as it includes merino wool hiking socks as a bonus.

The set is available in three weights—lightweight (165 g/m²), midweight (250 g/m²), and heavyweight (320 g/m²)—allowing you to choose the thickness that best suits your needs. The midweight option provides a good balance of warmth without being too bulky. One of the strengths of this set is its breathability, which helps regulate body temperature, keeping you comfortable in various weather conditions.

However, the care instructions specify hand washing and laying flat to dry, which might be less convenient compared to machine-washable alternatives. The seam construction appears to be designed to prevent rubbing and bunching, adding to the comfort. While the product is imported, it is backed by the Merino.tech Promise, ensuring customer satisfaction. This set is a great gift option due to its cool packaging and additional hiking socks. On the downside, some users might find the need for delicate care to be a bit cumbersome, especially for everyday use.