Why do clouds stay high up in the sky and not float at ground level?
The height of clouds is determined in a variety of ways by weather observers, but clouds DO float at the ground and when they do, they are referred to as fog. When air temperatures are very low (about minus 30 degrees Fahrenheit, or lower), fog droplets are often frozen and they are referred to as “ice fog.”
The idea that clouds “float” is actually incorrect. Clouds consist of tiny water droplets (or ice crystals) and, like all objects, they do fall, but at a very slow rate. Cloud droplets remain suspended in the atmosphere because they exist in an environment of gently rising air that overcomes the downward force of gravity. Only a very gentle upward movement of air is required.