All very cold air or artic blasts are going to have very dry air. The reason is cold air is no good at holding moister. The warmer the weather the better the chance of humidty. That is a hard question to answer, because the colder the air the drier it is.
Most plants are going to do better in a cold dry, then a wet cold, because of rot and fungus growth and some other things do to the cells of plants. I would rather see a dry month of 28F then I would like to see a wet month of 28F. But no plants are going to like artic blasts of below 0 temps, but if wet weather comes right before the hard freeze it might do you good because of the ice forming on the plants, this would help protect it from the cold.
I don't know if I helped answer any questions or not. 🙂

Definitely cold air cannot hold as much moisture as warm air. I guess I could say, along those lines, would 10 F with a dewpoint of, say, 8 (inversion situation; ok, maybe more of a Salt Lake inversion reading than a Boise or Tri-Cities inversion reading) be significantly different than 10 F with a dewpoint of -15 (the arctic blast)? Or would it just be the fact that the wind blows during the arctic blast, and it can (and has in the past) get a lot colder during such event?

I might be wrong but I would think 10 deg. to a plant is all the same, unless it has other factors in it like snow, rain, wind something like that because then those factors might transfer heat away from the plant.
Like people plants will hold some heat when compared to their surroundings. So when it rains or the wind blows then some of this heat is lost. I lose more plants to a cold wind then I do to just cold weather. I have found that my plants don't like it when it is 20F and a 60 mph wind 🙁 And that is what I see all to often here.