The Best Thermal Underwear
By Wirecutter
Ridge Women’s Aspect Midweight Merino Wool Base Layer Long Sleeve Shirt
"Our pick: A versatile long-sleeve top for women"
32 Degrees Men’s Lightweight Baselayer Crew Top
"Our pick: A synthetic long-sleeve top for men"
32 Degrees Men’s Lightweight Baselayer Legging
"Our pick: Synthetic leggings for men"
32 Degrees Women’s Lightweight Baselayer Crew Top
"Our pick: A synthetic long-sleeve top for women"
32 Degrees Women’s Lightweight Baselayer Legging
"Our pick: Synthetic leggings for women"
Smartwool Men’s Merino 150 Base Layer Long Sleeve
"Our pick: A merino wool top for long, active days outside"
Smartwool Women’s Merino 150 Base Layer Long Sleeve
"Our pick: A merino wool top for long, active days outside"
Minus33 Chocorua Men’s Midweight Wool Crew
"Our pick: A thicker wool top for men"
Minus33 Kancamagus Men’s Midweight Wool Bottom
"Our pick: Thicker wool leggings for men"
Minus33 Ossipee Women’s Midweight Wool Crew
"Our pick: A thicker wool top for women"
Minus33 Franconia Women’s Midweight Wool Bottom
"Our pick: Thicker wool leggings for women"
Under Armour Men’s ColdGear Base 3.0 Crew
"Our pick: If you’re going to get dirty"
Under Armour Women’s ColdGear Base 3.0 Crew
"Our pick: If you’re going to get dirty"
Le Bent Men’s Le Base 200 Lightweight Crew
"Our pick: A silky-smooth, formfitting top"
Le Bent Women’s Le Base 200 Lightweight Crew
"Our pick: A silky-smooth, formfitting top"
Le Bent Men’s Le Base 200 Lightweight Bottom
"Our pick: Our all-around favorite men’s leggings"
Le Bent Women’s Le Base 200 Lightweight Bottom
"Our pick: Our all-around favorite women’s leggings"
Icebreaker Men’s BodyFitZone Merino 260 Zone Long Sleeve Crewe
"Our pick: A techy wool top for high-output activities"
Icebreaker Women’s BodyFitZone Merino 260 Zone Long Sleeve Crewe
"Our pick: A techy wool top for high-output activities"
Icebreaker Men's BodyFitZone Merino 260 Zone Leggings
"Our pick: The best wool leggings we’ve tried"