Frosty Windshields

Every morning when I go out to my car during the winter, I am surprised by that morning's frost on my windshield. Even though I work from home, I go to the gym most mornings around 7am. Some mornings the frost is thick and requires heat and scraping. Other mornings it is thin and I can scrape it off without waiting for the car to warm up. The best frost is the lightest of all where it looks a network of crystals connected across the windshield.