My record was -63f/-53c. But it isnt all that bad. There is literally no weather/wind below about -40. No snow. No wind. No clouds. Only strange stuff like ice crystals falling from a clear sku, and snow that squeeks like walking on styrofoam. -35 and windy always felt colder than -50.

Ice crystals: https://youtu.be/4yBNmoa4htE