A couple weeks ago I was complaining about how my handling had slowly gone to shit and how I was finally fed up and wanted to do something about it. At first I had suspected my summer tires were crap (soft sidewalls—I still think it contributed), but when the issue followed me to my snow tires I suspected worn shocks. The feedback I got here mostly confirmed this, though the mileage seemed low.
This morning the handling was awesome. Temp of -14C. Now I bought the truck last October, which means I got used to the truck last winter, which was... cold. In fact when I switched to summers it was still cold. With this being the first properly cold day this winter, the way the handling issues followed me from the other tires seems to make sense.
Quick google on the effects of cold on shocks, and bingo. So pleased with myself.
Now I just have to find a set of shocks that will allow me to keep the winter handling in the summer.