One side is a lot more weathered than the other.

Camera right is south. The winter storms come mainly from the
south and south east. The sun is at camera left during the late
afternoon this time of the year, but over the course of a year
I think a lot more sunlight will come from camera right. So I'm
guessing that the weathering on the south side is from both
sunlight and the wind and rain from the winter storms.

Best viewed at original size.