Awww man, I don't have the thermometer. I so think the worst seen was about -10 or -15F (thank you insulated garage!! It was about 20F after a week of -10 or worse).
I did manage, however to drive the 5 with snows in about 18-20 inched of snow last winter! Well less driving and more like the old paddle wheel riverboats... (skimming along the surface of the snow).
Lesson Learned: more snow the ground clearance = snow/ice buildup in independent suspension and around drive shafts. I have never before had to melt ice from axles to prevent damage!