In most cases, these three layers are more than enough. However, if you're heading out on a multi-day expedition in the high mountains—where the weather can change quickly—bring a waterproof breathable shell to protect yourself from the elements. If you tend to get cold easily, pack a lightweight down or synthetic insulated jacket for extra warmth.
For your lower body, you have several options. A cross-country ski tight works well for shorter outings or milder temperatures. For longer expeditions or colder conditions, go for softshell-style ski pants. These windproof pants help retain warmth while shielding you from the cold. If you're sensitive to the cold, you can even wear a base layer underneath. And for multi-day trips, don’t forget to bring waterproof breathable pants for added protection in wet conditions.
Accessories matter too. A warm hat and neck gaiter are essential to protect against the cold. Choose gloves or mittens based on your preference, and always bring an extra pair in case the first gets wet. Same goes for socks—pack one or two spare pairs, especially if you’ll be crossing wet terrain. Nothing ruins a day faster than frozen feet.