What conditions characterize clear air turbulence (CAT)?

Clear air turbulence (CAT) is characterized by its occurrence in clear air, away from thunderstorms, and without any visible cloud formations. The correct answer highlights that CAT tends to appear in patches, indicating that it is not uniform and can be unpredictable. This type of turbulence often occurs at higher altitudes, typically at cruising altitudes of commercial aircraft, where there are no weather disturbances visible to pilots, making it particularly challenging to detect in advance.

In contrast to the correct answer, conditions such as occurring only during thunderstorms or being limited to below 10,000 feet do not accurately describe CAT, as this type of turbulence can occur well above this altitude and is not directly associated with thunderstorm activity. Similarly, the assertion that CAT occurs primarily in summer also does not reflect the reality of its occurrence, as it can happen year-round and is influenced more by atmospheric conditions rather than seasonal factors.