The Smartwool Classic Thermal Merino Women's 1/4 Zip Base Layer brings serious warmth to frigid days on the mountain. Made from 100% responsibly sourced merino wool, this midweight 250g/m² base layer naturally regulates temperature, wicks moisture, and resists odors to keep you warm, dry, and comfortable from first chair to last run. Its soft interlock knit fabric and updated slim fit make layering easy, while raglan sleeves and flatlock seams help prevent chafing and allow unrestricted movement. The quarter-zip design lets you quickly cool down when things heat up. Perfect for skiing, snowboarding, hiking, and everyday winter adventures, this women's merino wool base layer is a cold-weather essential you'll reach for all season.

Key Specifications

Material 100% Merino Wool

Fabric Weight 250 g/m²

Warmth Classic Thermal

Fit Slim Fit

Construction Interlock Knit

Neckline 1/4 Zip

Temperature Rating

Classic Thermal Merino

Designed for cold-weather layering, Classic Thermal Merino provides natural insulation, moisture management, and temperature regulation for active days in winter conditions.

Cool Conditions 25°F to 50°F

Cold Conditions Below 25°F

Smartwool Technologies

Moisture Management Technology

Odor Resistant Technology

Body Temperature Regulation Technology

100% Merino Wool Fabric

Start-Stop Activity

250 g/m² Midweight Merino Fabric

Key Technologies & Features

100% Merino Wool

Made entirely from responsibly sourced merino wool, this base layer provides natural moisture management, temperature regulation, and odor resistance. Merino fibers help maintain comfort through changing activity levels and temperatures, making them ideal for skiing, snowboarding, and other winter adventures.

Classic Thermal 250 g/m² Fabric

The midweight 250 g/m² interlock knit delivers dependable insulation for cold-weather conditions. Its soft construction provides warmth without excessive bulk, making it an excellent choice beneath insulated jackets, shells, and other winter layers.

Natural Moisture Management

Merino wool helps manage perspiration by absorbing moisture vapor and moving moisture away from the skin. This natural performance helps maintain comfort during active climbs, long ski runs, and changing temperatures throughout the day.

Temperature Regulation

Merino wool fibers naturally help regulate body temperature, providing insulation in cold conditions while allowing excess heat and moisture to escape as activity increases. This adaptability makes the base layer comfortable during both active movement and periods of rest.

Natural Odor Resistance

Merino wool naturally resists odor buildup, helping the base layer stay fresher through extended wear. This makes it a practical option for full days on the mountain, winter travel, and multi-day adventures.

Updated Slim Fit

The slim fit follows the natural contours of the body for comfortable next-to-skin layering. Its streamlined shape helps reduce bunching beneath additional layers while maintaining freedom of movement.

Quarter-Zip Ventilation

The quarter-zip neckline provides adjustable ventilation when activity levels increase. The 8-inch (20 cm) center-front zipper, measured on size Medium, makes it easy to release excess heat or zip up for additional coverage.

Raglan Sleeves

Raglan sleeve construction supports natural shoulder movement and helps improve comfort when layering beneath jackets or carrying a backpack. The design allows unrestricted movement during skiing, snowboarding, hiking, and other outdoor activities.

Flatlock Seams

Flatlock seam construction creates a smoother feel against the skin to help minimize rubbing and chafing. The back body seam wraps toward the front for added comfort and a streamlined fit.

Technical Specifications

Product	Smartwool Classic Thermal Merino Women's 1/4 Zip Base Layer
Gender	Women's
Material	100% Merino Wool
Fabric Weight	250 g/m²
Warmth Category	Classic Thermal
Fit	Slim
Fabric Construction	Interlock Knit
Neckline	Quarter Zip
Zipper Length	8 in / 20 cm (Size Medium)
Sleeves	Raglan
Seams	Flatlock Construction
Moisture Management	Natural Merino Wool
Odor Resistance	Natural Merino Wool
Temperature Regulation	Natural Merino Wool
Recommended Activities	Skiing, Snowboarding, Hiking, Winter Outdoor Activities
Country of Manufacture	Vietnam

Care Instructions

Machine Wash Warm, Gentle Cycle

Wash With Like Colors

Do Not Bleach

Tumble Dry Low

Cool Iron As Needed

Do Not Iron Decoration

Do Not Dry Clean

Women's Size & Fit Chart

Measurement	X-Small 0–2	Small 4–6	Medium 8–10	Large 12–14	X-Large 16–18
Chest	32–33"81.5–84 cm	34–35"86.5–89 cm	36–38"91.5–96.5 cm	39–40"99–101.5 cm	41–44"104–112 cm
Waist	24–25"61–63.5 cm	26–27"66–68.5 cm	28–30"71–76 cm	31–34"78.5–86 cm	35–38"89–96.5 cm
High Hip	31–32"78.5–81.5 cm	33–34"84–86.5 cm	35–36"89–91.5 cm	37–39"94–99 cm	40–43"101.5–109 cm
Hip	35–36"89–91.5 cm	37–38"94–96.5 cm	39–40"99–101.5 cm	41–43"104–109 cm	44–47"112–119.5 cm
Inseam	29–30"73.5–76 cm	30–31"76–78.5 cm	31–32"78.5–81.5 cm	32–33"81.5–84 cm	33–34"84–86.5 cm
Arm Length	27–28"68.5–71 cm	28–29"71–73.5 cm	29–30"73.5–76 cm	30–31"76–78.5 cm	31–32"78.5–81.5 cm