Why do clouds form at different altitudes?
Clouds are the result of a simple process: when the air is cooled down below the temperature at which it can sustain water as a gas, it forms droplets. That’s all. Now, there are many different reasons why the temperature of the air changes. But most typically: Warm air rises, cools down adiabatically and form the base of a nice cumulus cloud when reaching the so-called dew point temperature. But then, the air may also rise because it has to go over a mountain range. Or the air may sink without any rising when the sky is clear at night and the heat of the ground radiates back into space. If the soil is moist, a cloud will appear right above it. It is then fog. With the heat of the day, that fog may lift and form a stratus cloud. Another way to lift moist and warm and and produce clouds is when that air meets cold and dry polar air; it forms a front. Because warm air is lighter than cold one, the former will lift and generate clouds of all kinds. Sometimes clouds end in a high pressure
