What type of clouds can be found in stable air?

Stable air is characterized by a calm atmosphere where vertical movements are limited, often resulting in even temperatures and a lack of significant turbulence. In this environment, stratus clouds typically form. These clouds appear as uniform, grey layers covering the sky and are associated with steady, widespread precipitation, if any. Stratus clouds develop under stable conditions where the air is not conducive to strong vertical development, hence their flat, layered nature.

In contrast, cumulus clouds indicate rising air and thermal instability, which are not features of stable air. Cirrus clouds, while present in stable conditions, are high-altitude clouds that do not form as a result of surface air stability. Nimbus clouds imply the presence of significant moisture and turbulence, often leading to thunderstorms, which also suggests instability in the atmosphere. Thus, stratus clouds are the most appropriate type to associate with stable air conditions.