I once saw a photo of a person standing on top of mountain covered with snow but wearing T-shirt and shorts. How can this be? He said it was because it was warm up there. Since it was a sunny day does the snow reflects sunlight very well so the air near the mountain is at a high temperture but the ground is 0 celcius so very cold to touch. A good pair of insulating shoes should prevent heat leaking out of the person to the ground so summer ware is okay? But I was seen people wearing a lot on sunny days on top of snow mountains as well. So my answer could be wrong.