Yes, wind chill is a big factor. It refers to heat loss and when you are driving and creating maybe 50 mph wind through the radiator there is a major heat loss. Block off that wind with a winter front and you will be fine. If not, you better have strong anti freeze in the cooling system or it will gell up to the point that it won't flow anymore. Your engine will over heat while the radiator is froze up. Sounds funny but I've had it happen on at least one occasion.When you calculate the wind chill factor on a cold winter day the coolant in the radiator can freeze. .