Horizon Performance Extreme mountaineering sock review: a winter specialist with a premium price

A heavyweight winter sock, the Horizon Performance Extreme is designed to deliver warmth in extreme temperatures

Horizon Performance Extreme
(Image: © Horizon)

Advnture Verdict

A premium sock in every regard – including their price – these are warm, comfortable and hard-wearing winter socks that work brilliantly with big mountaineering boots. High-quality materials and construction deliver superb performance in the coldest conditions.


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Horizon Performance Extreme: first impressions 

According to the brand, the Horizon Performance Extreme is “the best cold weather sock that money can buy”. That’s a bold claim, but it demonstrates that Horizon have plenty of faith in their products. And to be fair, the premium materials used in their construction suggest they ought to live up to their billing. But did they make it into our best hiking socks buying guide?

They are made from a blend of PrimaLoft Silver yarns, merino wool, Isolfil polypropylene, hard-wearing nylon (including ultra-tough Cordura fibres in the toe and heel) and a little Lycra for stretch. That mix of synthetic fibres and natural wool is all about balancing comfort with durability, whilst also ensuring good warmth and excellent wicking performance. 

On the feet, they feel extremely soft and comfortable. The finishing is first-class, with no loose threads or uncomfortable seams. Inside the sock, terry loops feel great against the skin and trap plenty of warm air, while inspecting the outer reveals a zoned construction, with reinforced heel and toe areas plus ventilation channels along the top of the foot. 

Bear in mind that these are long socks that come up over the calf. They’re designed to be worn with winter mountaineering boots, though they’d also work well with wellies or fishing waders boots. An elasticated ribbed top ensures they stay put, while the rest of the sock is well-cushioned and very cosy. They’re definitely winter-ready but are overkill for other seasons unless you suffer from extremely cold feet.


• RRP: £45 (UK)
• Gender specificity: Unisex
Sizes available: S / M / L
• Materials: PrimaLoft Silver yarn (28%), Merino wool (28%), Isolfil polypropylene (29%), Nylon (8%), Cordura polyamide (5%), Lycra elastane (2%)
• Colors: Charcoal & Orange/ Charcoal & Cerise / Charcoal & Turquoise
• Compatibility: Winter hillwalking, mountaineering, fishing

Horizon Performance Extreme: on the trails 

We wore these socks with B1 and B2 mountaineering boots on winter hiking days in North Wales, and they performed magnificently, keeping our feet warm and dry throughout. They wick very well, managing moisture efficiently even in tough conditions. They’re quick-drying for such a chunky sock too. They also proved to be extremely comfortable, with no rubbing or hotspots. The Lycra in the fabric blend does a good job of keeping them in place, with no annoying slippage even when scrambling up steep mountain gullies or traversing scree-covered slopes. 

Admittedly, there is slightly less merino wool content (28%) here than in some other winter socks, but there’s still enough to deliver merino’s famous warmth and softness, as well as its temperature-regulating and natural antibacterial properties. We also suspect this will be a benefit in terms of long-term durability, since merino isn’t the toughest fibre. So, although the jury’s still out on that aspect for now, we’d feel pretty confident that they ought to last, even if subjected to tough use. They’re a thick and chunky knit, with plenty of nylon and Cordura yarns in the blend, both of which are known for their strength and abrasion resistance.

We can’t pretend that they still smelled perfectly fresh after a few days in the hills, especially compared to pure wool socks, but after putting them through a cool cycle in the washing machine, we left them to drip dry. We were pleased to find that they dried relatively quickly and retained their shape and softness too. Top marks.

The only obvious downside to these socks – other than the fact that they’re a fairly specialist bit of kit, since they’re too long and heavy to wear except in full-on winter conditions – is the high price. At a RRP of £45, these are a considered purchase indeed. Many might baulk at spending so much on a single pair of socks. Having said that, a quick search online revealed that if you shop around, you can pick them up for a fraction of that price.

Matthew Jones

An outdoors writer and editor, Matt Jones has been testing kit in the field for nearly a decade. Having worked for both the Ramblers and the Scouts, he knows one or two things about walking and camping, and loves all things adventure, particularly long-distance backpacking, wild camping and climbing mountains – especially in Wales. He’s based in Snowdonia and last year thru-hiked the Cambrian Way, which runs for 298 miles from Cardiff to Conwy, with a total ascent of 73,700 feet – that’s nearly 2½ times the height of Everest. Follow Matt on Instagram and Twitter.