What is frost?

Frost may be like a fairy forest on a windowpane in the winter. Frost is ice. It is formed when moist air comes against something very cold. The water vapor in the air freezes.
Frost on Windows is on the inside of the Windows. The moisture comes from the warm air inside the building. The Win­dows are cooled by the cold air outside. The frost on Windows is like the frost that forms on the coils of an electric refrigerator, but it is in much prettier patterns.
In the fall frost of ten forms on grass and roofs and bushes. Of course, it does not form unless the temperature goes below freezing. If the temperature is above freezing, dew forms instead.