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Aviation glossary

Radiation Fog

What is radiation fog?

FAA handbook figure illustrating radiation fog

Radiation fog forms when the ground cools on clear, calm nights, chilling the air just above the surface until it reaches its dew point and condenses into fog. It is most likely when skies are clear (allowing maximum radiational cooling) and moisture content is high (a narrow temperature/dew point spread). Think of it as "ground fog" that settles into low areas overnight and typically burns off as the sun warms the surface.

Also known as: ground fog

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