Convection occurs when a cold pot of water is placed on a stove burner that transfers heat to the bottom of the pan. As the water in the pan warms, it begins to bubble on the surface. Generally, convection transfers heat from a warm area to a cooler one.
The movement from a warm area to a cooler one is achieved by gases or liquids, according to the NC State University Climate Education website. Convection affects the weather, particularly in the formation of clouds and thunderstorms, as well as the formation of early-morning fog layers when the land mass temperature is warmer than the air above it.