They usually cover much of the sky. Cirrus clouds are high, thin, wispy and feathery. They are composed of tiny ice crystals. Middle Clouds Altocumulus clouds are middle level clouds with a puffy, patchy appearance. There are usually spaces between the clouds.
Altostratus clouds are middle level clouds.
They are light gray and uniform in appearance and generally cover most of the sky. Nimbostratus clouds are low and middle level clouds. They are dark gray with precipitation falling from them. The cloud bases are diffuse and difficult to determine because of falling precipitation. Low Clouds Cumulus clouds are low.