Clouds are classified using a Latin “Linnean”system based on genera and species, originally developed by Luke Howard, an amateur meteorologist and Quaker in 1802.
The modern classification scheme is based on Howard’s system and is detailed in The International Cloud Atlas, published by the World Meteorological Organization since 1896.
The WMO also classified clouds by
altitude and divided the troposphere into 3 levels:
Low-level Clouds: < 6,500 ft. Mid-level Clouds: 6,500 to 23,000 ft. High-level Clouds: 16,500 to 45,000 ft.