I feel kind of stupid asking this question, but here goes. I am not a newbie welder by any stretch, but it just occurred to me that I have never welded sheet metal in a building that was less than 65-70 degrees. Since the parts I am about to weld are structural sheet metal, I thought I would throw this out there. First, this is just plain old sheet metal(floor/trunk pans, quarters, frame rails, etc on a '70s GM). None of the newer high strength low alloy or anything like that. It will be MIG welded. Since fall seems to have just assaulted us in my area and there is no heat in the building I am working in, I am guessing the air temperature in the building when I weld will be in the upper 40s. So, will this colder temperature impact the strength/quality of my welds or am I concerned about nothing? Thanks in advance.