Tonight I noticed thread-like lines in or on my lightly-frosted windshield in the current single-digit temperatures. They did not resemble any kind of crystalline pattern and looked more like long strands of a spider web than anything else, though when I touched them there was nothing there. As the temperature rose inside the car, they slowly disappeared. If it matters, my windshield was completely replaced due to a stress crack in the one prior. Can anyone tell me what they were?
It could be humidity(in this case dew if it's in the morning) that just froze over your windshield. On my old car it will be more apparent in the wipers marks on the windshield as it would trap more humidity.
Happen to me often when getting colder temperature. When the car got hotter or outside temperature go up, it will just evaporate.