Fog is an accumulation of tiny water droplets or ice crystals suspended above the surface of the Earth. It forms when moist air is cooled below a specific temperature and some of the water vapor condenses (turns to tiny liquid droplets). By definition, the weather is considered foggy when we cannot see more than 1000 m ahead. In his book, Robert L. May described fog "as thick as white fizz" and near zero visibility (it was "dark and drear"), which suggests that the fog could have been one of two possible types: radiation fog or ice fog. Radiation fog happens when the ground cools the air above it by contact. Ice fog occurs when warm air interacts with extremely cold air and the water vapor changes directly into a solid, forming tiny ice crystals suspended in the air.
The ability of light to shine through fog varies according to the color of light.

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