I agree with the other responses. When the temp is in the teens or
below, add a washer solvent that has a higher alcohol content. I live in the
Great Lakes region, and I can tell you that this is normal.
There have been many times that I was tooling up the highway, it's hot
inside the car, but the windshield view starts getting smaller, and smaller,
until I slow down on a city street. The ice starts freezing at the top of
the windshield, and your "window of view", gets smaller and smaller. You
almost have to slump down into your seat, to get a good view. At this point,
you have the heat so far up, that you need to take your jacket off, and have
a t-shirt on, but the windshield is still frozen.