Fog is a Weather Phenomenon which can be described as a kind of cloud which remains in contact with the surface of the earth. The other forms of clouds are different from fog in that they do not touch the ground. Fog differs from mist by having different levels of density. It can reduce visibility to lower than 1 km. Fog is composed of droplets of water or occasionally even ice crystals. Fog can differ meteorologically, but in composition it remains the same.

Grand Banks in Canada is known to be the place having the highest frequency of fog in the world. Grand Banks happen to be the meeting point of the northern cold current called Labrador and the southern warm Gulf Stream current. This results in the frequent fog formation in the place. Other places which have more than 200 foggy days in a year are:

•  California

•  Argentina

•  Point Reyes

•  Newfoundland

Properties of fog :

•  The formation as well as dissipation of fog can take place very suddenly. It depends on the dew point. This is called Flash Fog .

•  Fog can sometimes give rise to precipitation like drizzle.

•  Sea fog is a common occurrence in coastal areas.

Different types of fog are :

•  Valley Fog is formed in winter in mountainous regions.

•  Steam Fog is locally formed when cold air passes over warm water.

•  Advection Fog happens with the passing of humid air over cooler surfaces by wind.

•  Radiation Fog occurs when land gets cooled in the evening by infrared radiation and when the sky is clear.

Fog can reduce visibility, therefore, the movement of land vehicles and air flights get hampered to a great extent.