No problem using the 590 in cold weather, but it is not double layered inside. So after some research, I am going to adapt one of the Traeger coats for it. It is the coat that will fit the Tex or new Pro 780. I measured the 780 and it is 32" wide. (odd number--usually 24" or 36" for most models). No problem with a little side overlap. However, will have to measure and cut out holes for the 3 exhaust vents. I worried how I would keep the fabric from sliding over those vents when opening and closing. Pending solution: I have ordered 2.5" flat round ceramic magnets, very powerful, to place over the fabric around those vents. The SS is 430 so is magnetic. Ceramic magnets are the best at keeping their magnetism with heat (good to 300* C ==572* F) and are not depleted till much hotter. Once I get it trimmed down as nec. I have a neighbor who does sewing for others. Will have her seam around the holes, etc. I can get a good sear now with the GGs but takes longer at 470* and gobbles pellets. Should pay for itself in short order on the long slow cooks.
"Someone asked Edmund Hillary why he climbed Everest. He answered Because it was there." Or something to that effect.