Types of Clouds Clouds can come in all sizes and shapes, and can form near the ground or high in the atmosphere. Clouds are groups of tiny water droplets or ice crystals in the sky. They are associated with different kinds of precipitation depending on the atmosphere's temperature. Cloud types are classified by height and appearance. The shape depends on the way the air moves around it. If air moves horizontally, clouds form in layers. However, clouds grow upward if air movement is vertical. Clouds are divided into 4 main groups; The high cloud group consists of Cirrus, Cirrostratus, and Cirrocumulus cl