Huh. He's still sleeping in our room at the moment and we haven't changed lighting/temp all that much. I realize the weather has changed but I didn't think it had changed the temp inside much for us yet.

We are in the process of weaning him off of swaddling. I imagine that is not helping.
...at least last night, he just didn't want to go to sleep - but wasn't crying and crying! :-/

He occasionally rolls from being on his tummy to being on his back, but hasn't rolled the other way yet. I think he has gotten distracted by standing up and that is currently taking all of his skill-learning juice. :-)

Thanks for the ideas! I will keep them in mind when we struggle with sleep... which I imagine will happen again tonight.