Sterring whell shimmy

I'm just curious. Rotated my tires at 25000 klms, changed front pads for the old were really making a mess of my rims. I also use spray wax at the car wash. On an off I have a slight shimmy up to 30 mph. It has been in the minus 40s for over a week. Could ice cause this, or any of the above
Just a dad, Thanks