In another thread I had proposed that as the room temp air is colder and colder, the draft would get stronger for a given chimney and outdoor temp. Doubt was cast by Joful below: I'm not sure. I know that temperature differential does not drive draft since I have set up more than a few stoves in wall tents with success and draft despite equal temps indoor/outdoor. I've also never had a flue reverse despite it often being warmer outside than inside. I know that pressure is lower with altitude but why would that matter? since the air in the flue sees no difference from outdoor air at each end. It just works, smoke goes up. Does it go up faster if the room air is colder?