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Best Way Reviews

Best wool socks for winter

Warm socks come down to two numbers: how much of the yarn is merino, and how much cushion there is to trap air. The trade-off is drying time.

3 products ranked Updated

Smartwool Mountaineer Classic Edition Maximum Cushion socks, the warmest pick in this guide

Smartwool

Our rankings are built from published testing by named outlets, not from our own lab. We earn a commission when you buy through our links, and it never changes the order.

The short answer

  1. 1 Smartwool Mountaineer Classic Edition Maximum Cushion Crew Warmest
  2. 2 Darn Tough Hiker Boot Full Cushion Midweight Warm and lasts for years
  3. 3 REI Co-op Merino Wool Expedition Socks As warm, for less

Prices checked 14 September 2026. They move constantly — the retailer's own page is the authority.

1 Warmest

Smartwool Mountaineer Classic Edition Maximum Cushion Crew

4 / 5

Our reading of OutdoorGearLab — 75/100, warmth 9/10, and their Best Cold Weather Sock , 2025

The winter sock: the most wool of any pick here and maximum cushioning, which scored 9 out of 10 for warmth. OutdoorGearLab's testers hiked in rain until their feet were wet, and they stayed warm. It is too hot for anything but cold weather, dries slowly, and its thickness can make a snug boot tight. Smartwool now sells it as the Mountaineer Classic Edition, still at maximum cushion and 74% merino.

Pros

  • Warmth 9/10
  • 74% merino, the highest here
  • Stayed warm when wet

Cons

  • Drying speed 3/10
  • Too warm above freezing
  • Thick enough to tighten a snug boot
Fibre
74% merino, per Smartwool
Where these findings come from
  • OutdoorGearLab: 75/100 and Best Cold Weather Sock; warmth 9, durability 8, comfort 8, drying speed 3; 74% merino, one of the highest wool contents tested; heavyweight
  • OutdoorGearLab: kept feet warm and comfortable even when soaked; overheated and felt itchy in moderate warmth; no elastic at the arch in the version tested
2 Warm and lasts for years

Darn Tough Hiker Boot Full Cushion Midweight

4 / 5

Our reading of OutdoorGearLab — 78/100, the top score of 19, with warmth 9/10 and durability 9/10 , 2025

As warm as the Smartwool on OutdoorGearLab's scale and the most durable sock in the test, with a lifetime warranty their testers have actually claimed on. It uses a little less wool and more nylon, which is where the toughness comes from, and it is slimmer, so it fits boots that the Smartwool crowds. If you buy one winter sock, this is the safer long-term buy.

Pros

  • Warmth 9/10 and durability 9/10
  • Lifetime warranty
  • Slimmer fit in boots

Cons

  • Too warm for summer
  • $30 a pair
Where these findings come from
  • OutdoorGearLab: 78/100, Best Overall; warmth 9, durability 9, comfort 8, drying speed 4; 66% merino, 32% nylon, 2% Lycra; midweight
  • OutdoorGearLab: lifetime warranty, which testers have used; outlasts other high-end wool brands in their experience; not for hot weather
3 As warm, for less

REI Co-op Merino Wool Expedition Socks

3.5 / 5

Our reading of OutdoorGearLab — 68/100, with warmth 9/10 , 2025

The same warmth score as the two above, with fewer points for comfort, and OutdoorGearLab describes it as a cheaper take on the Smartwool. A sensible buy for several pairs. No photograph or price: REI's store refuses our requests, and REI sells its own brand mainly in its shops, so the link is a search.

Pros

  • Warmth 9/10
  • Durability 8/10

Cons

  • Less comfortable than the Smartwool and Darn Tough
  • No photograph or verified price
Where these findings come from
  • OutdoorGearLab: 68/100; warmth 9, durability 8, comfort 7; offers many similar features to the Smartwool Mountaineer at a lower price

What makes a sock warm

Wool content. Merino stays warm when damp and handles sweat better than cotton or most synthetics. The warmest socks here are two-thirds or more merino.

Cushioning. Thick, looped cushioning traps air. A heavyweight sock is noticeably warmer than a lightweight one of the same wool.

Fit, which matters as much as either. A sock that makes a boot tight cuts circulation, and cold feet follow. If a thick sock squeezes, a slightly thinner one in a boot that fits will be warmer.

The trade-off

The warm socks in OutdoorGearLab's test were also the slowest to dry, scoring 3 and 4 out of 10. For a day of walking in the cold that rarely matters. For multi-day trips, pack a spare pair and rotate.

Where this comes from

We do not test socks. Our source wore 19 pairs for months, soaking and washing them in rivers, and scored warmth, durability and drying speed separately. Those scores are quoted on each pick.

What we are leaving out

Heated socks, and thin liner socks, which are for layering under these rather than replacing them.

Where this comes from

We did not test these. These people did.

Every score on this page rests on the testing below. The ranking is ours; the measurements are not. How we research.

  • OutdoorGearLab — 19 pairs worn for months of hiking, soaked, compressed, wrung out and washed in rivers, and scored separately for warmth, durability, comfort, wicking and drying speed. Updated April 2025.

Questions people ask

Does merino itch?
Fine merino rarely does, though very thick socks can feel scratchy on the calf when warm. Blends with nylon and elastane feel smoother.
How do I make wool socks last?
Wash them inside out on a cool, gentle cycle and avoid the tumble dryer on high heat. Rotating pairs so each one rests also helps the cushioning recover.

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