When is a ceiling indicated to be present in aviation terms?

In aviation, the term "ceiling" refers specifically to the lowest layer of clouds that cover more than half of the sky. Therefore, a ceiling is indicated when there is a broken or overcast sky. A broken sky consists of clouds covering between 5/8 and 7/8 of the sky, while an overcast sky has clouds covering more than 7/8. This definition is crucial for pilots, as it directly impacts their ability to operate safely and effectively, especially when navigating approaches and landings, which often require specific visibility and ceiling conditions.

Other options do not meet the criteria for a ceiling in aviation. Scattered clouds might appear in the sky without contributing to a ceiling since they cover less than half. Clear visibility alone does not imply a ceiling because the presence of clouds is necessary to define it. Lastly, the absence of clouds means there is no ceiling at all. Thus, the presence of broken or overcast clouds is essential to establish a ceiling in aviation.