-30 c is the coldest I've skied (before wind chill), and that is definitely my limit. It's painfully cold, and I hate the wind in my face, and skis don't run so smoothly in the sticky cold snow. I won't go if it's colder, and resorts won't open here if the windchill is -40 or below. Having said that that is my coldest though, I should mention that skiing between -18c and -25c here is a pretty regular occurence...