Not a meteorologist in the bunch.
Dew is a result of the surface temp of the object it forms on combined with the amount of water in the air. As objects cool at night they radiate heat and moisture in the air and water condenses on the surface. (heat always go to the cold never ever the other way around. 2nd law of thermodynamics, and the first law of the universe higher order to lower order). Anyway if the air is relatively cold enough you get frost or ice.
The temperature at which dew forms is called the Dew Point. If for some reason you have a lot of water in the air and there is a sudden cooling of this air you get Fog sort of spontaneous dew that then settles on everything. Hence the camping under a tree you don't get as wet.
Warm air can hold more water because there is more distance between the molecules to hold the H2O and they are moving faster. Cold air is denser and slower moving thus condensing (squeezing if you will) the water out more easily.
Never take off from Denvers airport with a fully loaded plane on a hot day. You might crash like my daughters plane did. (no one was harmed the landing gear were crushed but thats all, Oh and the smell inside the plane from the...well you know...everyone was scared) More molecule of air densely packed together give lift hot air doesn't.
just a bit of science form the 9th grade...if you were paying attention!
Gnat