What is the maximum recorded visibility in aviation meteorology observations?

In aviation meteorology observations, the maximum recorded visibility is traditionally up to 10 statute miles (sm). This standard is set because visibility beyond 10 sm is often considered to be effectively unlimited for practical purposes in aviation operations. Flight operations typically do not require more than this measurement, as it is sufficient to ensure safe flying conditions, especially in terms of takeoff and landing.

While advanced instruments and technologies may measure visibility far beyond 10 sm, meteorologists cap the visibility reported at this level to provide standardized and easily interpreted information for pilots and air traffic controllers. In specific situations, visibility may be reported as "greater than 10 sm", but for routine observations, the maximum is kept at 10 sm for simplicity and clarity in communication.

Other options, while they suggest alternative visibility measurements, do not reflect the standard maximum used in aviation reports. For example, 25 sm might imply greater visibility conditions, but it ultimately leads to the understanding that such measurements are typically referenced as "unlimited" or simply not reported beyond 10 sm.