Cloud
A visible aggregate of tiny water droplets and/or ice crystals in the atmosphere above the Earth’s surface
High Clouds
Cirrus
Cirrostratus
Cirrocumulus
Composed Almost Exclusively of Ice Crystals
Rather Thin
Bases mainly between 16,000 and 43,000 ft AGL over mid-latitudes (Latitudes between 30 - 60°)
Middle Clouds
Altostratus
Altocumulus
Composed of Water Drops and Ice Crystals
Bases mainly between 6,500 and 23,000 ft AGL over mid-latitudes
Low Clouds
Stratus
Stratocumulus
Nimbostratus
Mostly Water Droplets Except in Cold Weather
Bases mainly from the surface to 6,500 ft AGL
Vertical Clouds
Cumulus congestus
Cumulonimbus