Definition
A deposit of frozen water droplets on the ground or on exposed surfaces, formed when dew that has already settled freezes after the surface temperature drops below freezing. Unlike frost, which forms directly from water vapor, white dew begins as liquid dew and then freezes in place.
Plain English
Dew that froze. Water collects on a surface as normal dew, then the temperature drops below freezing and the dew turns to ice.
Context Anchor
A pilot may notice white dew during a cold, damp preflight inspection, especially on wings, windshields, struts, or other exposed aircraft surfaces.
Derivation
Called 'white' because the frozen droplets scatter light and look pale or white on the surface, distinguishing it from ordinary clear dew.
Why Pilots Care
It signals possible surface icing that must be removed before flight.
Grounding Statement
Picture a cold morning where the airplane looked wet at first, but the moisture has frozen into a thin white coating by the time you arrive.
Intuition Check
White dew is not just harmless wetness that happens to look pale. In this use, it means the dew has frozen, so it should be treated as ice on the aircraft.
Example Sentence 1
After a cold, clear night, the pilot found white dew on the wings and had the aircraft de-iced before departure.
Example Sentence 2
White dew on the taxiway showed that overnight temperatures had dropped below freezing.