Subject: Exactly how does dew form?

What is the relationship between temperature of the air and the item that the dew forms on and the relative humidity for dew to form? I am trying to learn how dew is formed so that I may predict when dew will form on my dad's car. What weather data will I need, and what formula would I use? Also if I may, why doesn't dew form outside under an overhang or car port? Thanks I have read the answers to other questions on dew, but they did not explain how it is formed with the amount of detail I would need to predict when dew would form outside on my dad's car. Thanks Chris GREAT SITE. I love science!!!!

Re: Exactly how does dew form?