Fog

Do you know when fog becomes mist, or how you can catch fog? Tackle this Fog Puzzle Exhibition to find out

Fog
image by Ricardo Gomez Angel

Fog begins to form when water vapor condenses into tiny liquid water droplets suspended in the air. This occurs when the difference between air temperature and dew point is less than 2.5 °C or 4 °F. These water droplets make up the fog or mist. There are many types of fog, such as evaporation fog, advection fog, radiation fog, and upslope fog. The thickness of fog varies depending on the atmosphere, temperature, weather, and location.

Fog generally forms when the relative humidity reaches 100% at ground level. Its ability to form suddenly and disappear as quickly is determined by what side of the dewpoint the temperature registers. The sudden formation of fog is known as “flash fog”.