Difference between Mist and Fog
When warm air passes gently over colder sea or land surface the air in contact with the colder surface also cools. If the air is cooled below its dew point, the air releases moisture and the water droplets settle on the land surface this is DEW. Some of the water droplets settle on the dust particles, pollutants, salt present in the air. These water droplets remain suspended in the air as they are very small and light. These suspended water droplets form MIST.
MIST: size of water droplets is less than 1 micron, and the visibility is about 1 Km.
When the size of waterdroplets increases to between 1 to 10 microns the mist becomes dense and ,is called as FOG.
FOG: size of water droplets 1 to 10 microns and visibility less than 1 KM.
Mist is always there before and after FOG.