THORLO'S Extreme Cold Over Calf Mountaineering Socks 38-42 (Grey/Black)

When the mercury plummets and the trail turns punishing, reliable thermal socks are non-negotiable. The THORLO'S Extreme Cold Over Calf Mountaineering Socks combine a high-performance Thor-Lon® acrylic blend with dense cushioning and an over-calf silhouette—purpose-built for mountaineering, winter expeditions, and sub-zero treks. This is serious cold-weather gear that keeps feet warm, dry, and blisters at bay.

Overview

THORLO'S has engineered these socks for extreme cold with a proprietary Thor-Lon® fibre system that delivers outstanding thermal efficiency while remaining soft and breathable. The heavy cushioning pad absorbs shock during long descents on rocky trails, while integrated arch support stabilises the foot and reduces fatigue. The over-calf length seals out snow and cold air, making them an ideal layering piece for high-altitude adventures.

Each pair is constructed with 85% Thor-Lon® Acrylic, 13% Nylon, and 2% Spandex—a blend that provides durability, stretch retention, and quick moisture transport. Low-profile toe seams eliminate friction, and ventilation channels help regulate temperature during high-output climbs. Whether you're tackling an ice climb or setting up camp in deep winter, these socks are a trusted companion.

What stands out

• Thor-Lon® fibres: superior softness, strength, and warmth-to-weight ratio
• Heavy cushioning: targeted impact absorption in heel, toe, and forefoot
• Over-calf length: maximum coverage and protection against extreme cold
• Integrated arch support: reduces foot fatigue and improves stability
• Flat toe seam: minimises blister risk on long treks
• Moisture-wicking: keeps feet dry even during intense activity

Technical details

• Material: 85% Thor-Lon® Acrylic, 13% Nylon, 2% Spandex
• Thermal Rating: Extreme Cold
• Cushioning Level: Heavy
• Sock Length: Over Calf
• Arch Support: Integrated
• Toe Seam: Low-profile / Flat
• Breathability: Moderate (optimised for warmth)
• Odour Resistance: Yes
• Durability: High - reinforced in high-stress zones
• Size: EU 38-42 (UK 6-9, US Men's 6-9, US Women's 7-10)
• Colour: Grey/Black
• Care: Machine wash warm, tumble dry low

Our verdict

For mountaineers and winter sports enthusiasts who demand uncompromising warmth, the THORLO'S Extreme Cold Over Calf socks are a stellar choice. They combine proven materials, thoughtful construction, and a comfort-focused fit—exactly what you need when the weather is anything but friendly.