With no idea on the wind chill, I managed last week's (two weeks ago?? *shrugs*) -39 snap here in North West Alberta, Canada no worse off then last year. I just broke out the wool kilt hose and went to work. Layers on the upper half, and a thermal sock on over the hose in regular Dakota steel toes, and there wern't any issues.

Thankfully the nerves are few and far between in the knees in the wind though, I can say that much. Always a pleasure to bring some colour to the oilfield.