Rubber looses a lot of flexiblity when it gets cold, so a bit of slowness at the top of the window's travel is to be expected.
Cleaning the tracks, both in the window frame and behind the door panel will help. Remove that cheap factory grease and put in some clean lithium lube (I use white grease). I have experimented with White Lightning before too -a little messy to apply, but it seemed to work.

Also, there's a moisture issue. If any condensation gets in the door panel (if you removed/tore those plastic vapor barriers behind the panel) there will be a moisture issue inside of the door skin. This contributed to the occasional cold weather related failure of my passenger side door lock (water would collect within the gearing, freezing up the works, and preventing the lock from moving). This also slowed my window travel.

If everything is dry and lubed, you won't have a problem. Once everything behind the skin is cleaned up, you can replace that vapor barrier with some Visqueen sheeting and a little flashing caulk.
Once I had the mechanics of the door completely separated from the heat of the interior, all of my problems disappeared.
Windows and locks operated smoothly to beyond -50F.