I attempted to roast outside tonight. The ambient temp out there is around 38F. Roasted it for 25 minutes and I may have missed it, but I don't think I even heard first crack. The coffee was fairly dark but I did not get the results I was looking for.
Moved the operation back inside again and roasted another batch. About 4.5 minutes until first crack and went to 6 minutes total. This was much closer to what I was looking for. Nice dark roast, much more even. I think I can live with the small amount of smoke from indoor roasting, at least during the winter.
I was definitely under-roasting with my first few batches.
When it's cold out I put the hot air popper in a ~3 gallon bucket (the kind you can get from the walmart bakery) and leave the popper top/deflector on so the air is redirected back down to the bottom of the bucket so it recirculates the hot air. Works like a champ.