Weather conditions necessary for mist/fog (night/morning)

It's been many years since high school . Does anyone remember what weather conditions are necesary for mist/fog to form? (And is there a difference?)

I seem to remember something about 'ground colder than air'. In that respect, ground fog (i.e. waist-high) in the morning during winter/spring makes sense (air warming up due to sunlight but ground still cold from night).

(I know I could probably google this but my internet connection is really, really slow.)

Thanks in advance.

Thanks - I'll check it out.

(As an example of how slow my connection is, it took me 2 minutes, 59 seconds to sign onto the internet, come directly to this forum, then click on this thread and have the page load. Pathetic.)