What does "cloud cover" refer to in aviation?

In aviation, "cloud cover" specifically refers to the extent of the sky that is obscured by clouds. This measurement is important for pilots as it can significantly impact visibility and flight operations. When assessing cloud cover, aviation authorities typically express it in terms of oktas, or eighths of the sky that are covered by clouds. Understanding cloud cover is essential for planning and executing flight maneuvers safely, as it influences takeoff, landing decisions, and overall flight safety.

The other options, while they may touch on aspects related to weather, do not accurately define cloud cover. Temperature variability refers to how temperatures change in a specific area, which is not directly linked to the concept of cloud cover. The number of clouds visible above the ground could relate to visual observation but doesn’t capture the concept of how much of the sky is covered by clouds. Weather forecasting techniques encompass the methods used to predict weather, which again, is a distinct subject not related to the direct measurement of cloud cover itself.