I know that short of a distance and that big of a temp spread is ridiculous. We had a heavy frost also. Almost looked like it snowed on the truck.... These microclimates can get crazy around here. I think what helps me is that we are in a bowl but the valley is directly in front of me. I think that helps to filter the cold in and out for us. We don't get trapped with the inversion in my opinion. But all that could just be BS lol.