Most clouds form in the atmosphere when moist air 1. rises, expands, and cools to the dewpoint 2. rises, expands, and warms to the dewpointt

Most clouds form in the atmosphere when moist air rises expands and cool to the dew point. When the air above reaches its saturation point, the water vapor is attracted to dust particles which when they accumulate the hold on tho each other and form clouds. Evaporation and condensation is what causes saturation above. When the clouds become heavy enough with moisture, the water then fall to earth as rain.