Stratus is usually composed of small water droplets. When very thin, Stratus may produce a corona around the Sun or Moon. At low temperatures, Stratus may consist of small ice particles. The ice cloud is usually thin, and on rare occasions, may produce halo phenomena.
Stratus, when dense or thick, often contains drizzle droplets and sometimes snow or snow grains. It may then have a dark or even a threatening appearance.
Stratus with a low optical thickness, usually of the variety translucidus, often shows a smoky greyish tint like that of fog, when viewed at more than 90° from the Sun.