foggy

Foggy is an adjective describing weather or scenery that is covered by fog or has a fog-like quality in light or visibility. In meteorology, fog is a cloud that forms at the ground level, reducing visibility. A foggy day typically features low visibility, sometimes less than 1 kilometer, which can affect road, maritime, and air travel.

Fog forms when moist air cools to its dew point or when humid air passes over a cooler surface, causing water vapor to condense into tiny droplets suspended in the air. Common types include radiation fog (overnight chill and clear skies), advection fog (warm, moist air moving over a cool surface), upslope fog (air rising along terrain), and freezing fog (fog droplets become ice crystals at or below 0°C).

In forecasts and reports, foggy conditions are noted as such. Fog reduces horizon and texture, and in aviation, fog can lead to delays or changes in approach and landing procedures; in road transport, reduced visibility slows traffic and increases accident risk.

Figuratively, foggy can describe mental states such as a foggy memory, foggy thinking, or unclear judgment, meaning confusion or lack of clarity.

The word foggy is derived from fog, with a long-standing use in English to describe weather where a cloud is in contact with the ground.