I feel your pain, having gone through this before. The problem is that the valves are closed, not open, and the lifters don't have enough oil in them to function. I really don't know how much this will help with the cold weather, but perhaps changing to a very light weight oil and cranking several minutes without the sparkplugs will finally get the oil up into the lifters so they will function.

While you are doing this, disable the fuel injection by pulling the fuel pump fuse so you don't flood the engine. While the plugs are out, check and see if they are wet with fuel and dry them out if they are. Some brands, especially cheap old Champions, have porous porceline and won't ever spark if the porceline is soaked with gas. I use a propane torch to burn off any fuel on them.

Hope you get it fired up soon!