Stratus comes from a Latin word that means layers. They are visible as layers of clouds that span a good portion of the sky. These clouds are thicker than the cirrus clouds and can often create shadows on the ground. They are not thick enough to make the moon and sun disappear. Common stratus clouds include Altostratus and Nimbostratus.

Did you know…
There is a difference between Altocumulus and Cirrocumulus: Altocumulus is a mid-altitude, dark grey or blue cloud, whiles cirrocumulus is whitish, higher altitude.

Altostratus:

“Alto” means ‘Mid-altitude’. Altostratus is a medium altitude cloud, often with stratus (layered) character. It is blue-grey, or dark grey and indicates that there could be rain in a couple of days. This cloud is also made up of ice crystals and a lot of water droplets. During a sunny day, such clouds can dim the sun’s shine. Altostratus clouds are often featureless and without any distinctive character.

Nimbostratus

Nimbos mean rain-bearing. Nimbostratus clouds are also midlevel to low-level clouds, but thicker, heavier, and darker than Altostratus clouds. With these clouds, the sun cannot be seen at all. They also cover the entire sky and come with light to moderate rain or snow, usually lasting for the whole day.