When it comes to Quick Ways to Ruin a Ski Trip, foot problems are near the top, with missing your flight and forgetting the moisturizer.
When planning your trip to the snow, you decide where you're going and what you're doing based on whether you've done it before, and then get your ski jacket, pants, thermals, and other stuff together. Maybe the pile is pretty big, but socks as an overall part of that are pretty small. Extras are pretty easy to fit in, but not valuable if they are not going to work for you through the whole trip.
Some key factors:
- What kind of activities are you planning?
- Are they pretty similar?
- Will you have access to laundry?
In skiing and snowboarding, your boots are your main interface with the binding and board or skis, and your socks can help that be a close and comfortable connection. Socks provide two main functions; managing moisture and improving the fit of footwear. Warmth will be provided by activity level and boot contruction, not the sock. A bulky 'thermal' sock in technical snowsports boots could restrict circulation, making warm feet almost impossible.
Your feet sweat no matter what the conditions are, and so wicking that moisture off your skin is critical, especially in snowsport boots that have little capacity for venting or breathability. Both types of boots have very thick foam linings to provide insulation and a very snug fit, so the sock must also work to tweak the fit without getting in the way. At one time a wicking liner and cushioning oversock would be worn together, but modern socks handle both tasks well and reduce bulk in the boot.
Activity-specific
Ski socks are over-the-calf to stay up and out of the boot and provide some compression support, as well as cushion the shin, since most of your skiing will be done leaning into the boot, while being much thinner around the calf to reduce bulk. Cushioning will be placed under the entire foot and seams should be as low-profile as possible. The choice of cushioning weight will depend on your boots.
When buying ski boots, the thermofoam liner is molded to you, and so the sock should be as thin as possible, just enough to smooth out the surface of the foam and keep your skin dry and protected.
If you are renting equipment, the fit will not be customized for you, so a medium-cushion sock will help fill in the gaps and improve the ride. The same ski sock shoudl serve of cross-country as well, just keep in mind your overall aerobic activity will be much higher and so moisture control even more important.
Snowboarding boots and position/style are different enough that a specific sock will help considerably. They are also over-the-calf but will have a less technical look than ski socks. The boot fit is not as customized and the boots have a more conventional lace-up design, so a snowboard sock is much more like a very tall hiking sock, with medium cushioning all the way around the foot, calf, and shin. The majority of snowboarders wear a medium weight sock.
Materials
Good socks will be made of high quality acrylic or merino wool yarns, with the finer fibers against the skin and heavier, more durable yarn on the outside. Synthetic socks will have better loft retention, meaning the sock will provide better cushioning over multiple wearings without washing, and better wicking at higher temperatures. The merino wool will will handle moisture better at lower temperatures, and start out with higher loft in the cushioning and a softer feel, but will become flatter over several wearings.
The stretch in technical socks is provided mostly by Lycra and Spandex fibers, which have little capacity to handle moisture, cushion, or insulate. When combined with acrylic or merino that excel at loft and wicking, you'll get consistent fit and drier skin throughout your activity.
When and how you wash your socks is where the biggest difference will appear. Synthetic fabrics in general have lower microbial resistance, so they will tend to funk up faster and eventually retain the smell. Merino wool, no matter what brand, is naturally anti-microbial, and so can be worn several times without making themselves unwelcome. As far as wash and wear, for similar weights of cushioning, the socks will air or machine dry at about the same rate. On the foot, synthetics will dry faster, but you may amplify the funk.
Your choice should be the most comfortable for you, so try several combinations of socks and footwear before you leave on your adventure, and take an extra pair of the socks that work - you won't regret it.