Conditions for frost to occur

Photo courtesy of Dr. Richard Carlson, Iowa State University

Frost: a covering of minute ice crystals on a cold surface

"Ice crystals" suggests we need to know something about moisture in the frozen form.

"cold" means that a low temperature is necessary.

"surface" indicates where the low temperature is measured.

Note:

Large accumulations of frost may result if conditions are favorable for rapid frost formation. Slowly forming frost, on the other hand, may either be worn off by vehicular traffic or have insufficient time to develop a large accumulation.

What causes frost to form?

What are the differences between road frost and bridge frost?