In February, I'm going to Big Sky, Montana, and I'm looking for recommendations for Athleta pants for the cold weather. Unfortunately, I don't think leggings will cut in there because it will be close to 20 degrees.
The fleece lined pants by athleta are perfect for athletic winter outdoor activities like brisk walks and xc skiing. I have the lined yoga flare pants and work outdoors. Swear by them. Live in Cincinnati, from Upstate NY.
I live in the Colorado Rockies and love any of Athleta's Polartec tights, pants or joggers. Polartec is the ultimate cold weather fabric IMHO. If you will be skiing or snowshoeing, check Athleta's ski pant offerings. I am partial to the boot cut ski pants (from last year) with a base layer underneath. Enjoy your trip!