I've found that as the temps get colder the squeaks get louder. Maybe because everything contracts a little and starts rubbing. I have a squeak in the center of the dash that wasn't there a couple of weeks ago when it was warmer, at least that's where I think it is. I just let it squeak and wait until it warms up again. You will drive yourself crazy trying to find it and you'll end up in the nut house trying to fix it.
2014 C-Max Energi