If you leave the windows slightly cracked open especially when the car is sitting in the sun, it will eventually go away. I am in the Upper Peninsula and had the same issues. Being that the snow comes inside off my shoes and I only drive a few miles at a time, the frost accumulated quickly.
I recommend just leaving the windows cracked and eventually they will defrost. Just because it is cold outside doesn't mean evaporation will stop (it just goes really slow). Keeping the windows clean will allow the frost to form in a uniform film opposed to spots or lines where you tired to scrape it off. Another reason why you can tell your friends or kids to not touch the windows.