I can currently stay pretty comfortable down to 0°F with bar pogies and a thick + thin glove on each hand. However, it's been about -15°F in the mornings where I live and my fingers feel like they're about to fall off by the time I get to work. I already don't have great circulation to my hands and, predictably, it gets even worse when my body is ready to sacrifice my appendages to keep my core temperature up (even though I'm sweating by the time I get there sometimes).