There's still almost no moisture in the air at 0F, no matter if you're on the coast are in the middle of the continent. The air just can't hold that much water at that temp.

When it's warm:

   50% humidity @ 40C: 25.43 g/kg (grams of water / kg of air)
   90% humidity @ 40C: 45.78 g/kg

When it's cold:

   50% humidity @ -18C (~0F): 0.68 g/kg
   90% humidity @ -18C (~0F): 1.23 g/kg

There's just not enough there to cause any noticeable affect.

But you don't have to take my word for it, the US National Weather Service agrees:

https://www.weather.gov/safety/cold-wind-chill-chart

"The results of the tests showed that relative humidity was an insignificant weather parameter, affecting the outcome to less than 1 degree"