I too am having this problem just the last few weeks with Teddy. He's almost 11 months old, and I can walk him outside till my hands turn blue (its cold here too) and 9 out of 10 times he won't go until we come back in.
... Never had a problem before, he was a BREEZE to potty train (the first time). Are there aliens out there forcing our furbabies to poop in the house or what ??????