Why, on some mornings, do I have to scrape ice from my front and back car windows, but not from the sides?

Question: Why, on some mornings, do I have to scrape ice from my front and back car windows, but not from the sides?

Answer: The most likely explanation is that the front and back windows of the car are more horizontal than the sides. When they lose their heat, it goes straight up into space, which means they cool down more than the side windows. Therefore, any condensation that forms on the front and back windows probably freezes quicker than that on the sides.