High Quality Content by WIKIPEDIA articles! Cumulus clouds are a type of low-level cloud that can have noticeable vertical development and clearly defined edges. Cumulo- means "heap" in Latin. They are often described as "puffy" or "cotton-like" in appearance, and are generally less than 6,500 feet (2,000 m) in altitude, unless they are of the vertical cumulus congestus form. Cumulus clouds may appear alone, in lines, or in clusters. Cumulus clouds are often precursors of other types of clouds, such as cumulonimbus, when influenced by weather factors such as instability, moisture, and temperature gradient. Cumulus clouds are part of the larger category of cumuliform clouds, which include stratocumulus clouds, cumulonimbus clouds, cirrocumulus clouds, and altocumulus clouds.