What are the four types of fog?

The four types of fog are radiation fog, advection fog, upslope fog, and evaporation fog. Radiation fog forms on cool, clear nights when the ground loses heat rapidly. Advection fog occurs when warm, moist air moves over a cold surface. Upslope fog is formed when moist air is forced to rise up a slope or mountain. Evaporation fog occurs when air near the surface is cooled to its dew point by evaporation.