Altostratus cloud
© The Great Cloudwatcher
Situated at an altitude of 6,500 to 20,000 feet, Altostratus clouds can easily be mistaken as cirrostratus, as they both belong to the stratiform genus-type which means they both look like a single layer in the sky. However, altostrati tend to have a more grey or blue-grey appearance. These clouds are made of ice crystals and if thin enough, the sun can shine through.
Altostratus can produce light rain. If precipitations become heavier and more frequent, the cloud can thicken into a nimbostratus. This cloud can also form ahead of a storm with rain, or snow in winter.