It started snowing where I live and I decided to take a few shots with the Droid. I learned something today that I should have known. Before you start taking pictures, you may want to wipe the camera lens off. First picture is before wipe. Second is after wipe. I'm so use to having a lens cap on a camera I didn't even stop to think the lens might be smudged on the phone.
It was determined that the wiping the screen excitement was not valid and there was a date error every 24.5 days "if I remember right... when that day tripped.. everyone's camera improved and some assumed it was from wiping the lens.
In your case, its likely your lens fogged up from walking out of a hot room into the frigid cold..... when you wiped the lens, it didn't refog.
I could be wrong...thats just a guess.