Hi Hoosier... I have cooked a split turkey breast at 350, leg of lamb at 225 and prime rib at 225 the past week in ambient temps in the mid teens with no issues. All came out the same, if not better (don't know why) than when I cooked in much warmer ambient temps. Although not single digits, I have not seen a reason to get a cold weather blanket yet. Other than the one I use to go in and out of the house to the RT.....hahahaha.