What defines fog in meteorological terms?

Fog is defined in meteorological terms as minute water droplets suspended in the air that significantly reduce horizontal visibility at the surface. This phenomenon occurs when the air temperature and dew point converge, causing water vapor to condense into tiny droplets. When these droplets accumulate close to the ground, they create a visible cloud layer that reduces visibility to less than 1 kilometer (or about 0.62 miles).

The presence of these tiny water droplets in fog is crucial, as it differentiates fog from other weather conditions. While smoke, cloud formations, and temperature mixes can affect visibility and weather conditions, it is specifically the suspension of water droplets that meets the precise definition of fog. This understanding is important for meteorological observations and issuing weather advisories, as it impacts travel safety and various outdoor activities.