Which weather condition is most likely with the presence of cumulonimbus clouds?

The presence of cumulonimbus clouds is closely associated with thunderstorms and severe turbulence. Cumulonimbus clouds are towering, vertically-developed clouds that can reach high altitudes and are indicative of strong atmospheric instability. These clouds develop when warm, moist air rises rapidly, leading to the formation of significant precipitation and storm activity.

As they mature, cumulonimbus clouds can produce severe weather phenomena such as heavy rain, lightning, thunder, hail, and even tornadoes. The upward and downward air currents within and around these clouds contribute to severe turbulence, making them a critical factor for aircraft safety.

In comparison, the other options describe weather conditions that are not typical of cumulonimbus clouds. For instance, calm and stable conditions would tend to be associated with stratiform clouds, not the dynamic and unstable nature of cumulonimbus. Light rain and moderate temperatures might occur under different cloud types but would not encapsulate the often severe precipitation from cumulonimbus clouds. Lastly, clear and dry weather signifies high-pressure systems, which are directly opposite to the stormy conditions associated with cumulonimbus clouds.