Here in Australia, we are far from having frosty nights. In fact, we are currently rather worried about keeping ourselves safe from fire dangers due to the extreme and continuous heat in most parts of the country. However, I know my readers are not only from Australia and also, this is a tip that needs to be noted for the days when it will become handy even if it is not now.
If you would like to prevent your car windows from frosting, coat them with a vinegar solution overnight (3 parts white distilled vinegar to 1 part water).
Have a safe day!