Stratus clouds are low-level clouds that form in calm, stable conditions when gentle breezes raise cool, moist air over colder land or ocean surfaces. They are characterized by horizontal layering with a uniform base, as opposed to convective or cumuliform clouds formed by rising thermals. Here are some key characteristics of stratus clouds:

• Height of base: 0 - 1,200 ft
• Shape: layered, flattened or spread out
• Color: varying in color from dark gray to nearly white
• Precipitation: Stratus clouds may produce a light drizzle or a small amount of snow

Stratus clouds look like featureless gray to white sheets of cloud. They can be composed of water droplets, supercooled water droplets, or ice crystals depending upon the ambient temperature. Stratus clouds are the lowest-lying cloud type and sometimes appear at the surface in the form of mist or fog. There are two defined species of stratus clouds: Stratus nebulosus, which is a featureless, dark layer capable of producing drizzle, and Stratus fractus, which is a stratus layer that is starting to break up or dissipate, leading to breaks in the cloud.