My running is different this winter than during my winters in New England. New England is colder than Utah. I think, that for the same reading in (F), the New England winters feel about 10 degrees (F) colder than they do in Utah. This difference in feel is probably due to the higher humidity in the East.
When I ran during New England winters, my whole purpose was to survive. I ran slower due to ice, and I only ran for an hour, because my body started to feel cold after an hour. I wore 5 layers during the coldest part of the winter. By contrast, here in Utah the streets and the Jordan River Parkway are clear of ice, and I'm able to run for two hours and feel fine. I wear 3 layers during the coldest part and usually only wear 2 layers. I'll be starting speed training this week by running fartleks on Saturday, and I never would even consider doing speed training in January in New England.
When I speak of so many layers, I'm referring to layers over my core. I've never worn more than two layers on my legs and just one layer on the bottom part of my legs. My legs don't seem to feel the cold.