Visibility is reported in what units?

Visibility in aviation reports is primarily expressed in statute miles (SM) in the United States. This unit provides a clear and familiar measure for pilots and air traffic controllers, facilitating effective communication and understanding of visibility conditions relevant to flight safety and operations.

Statute miles are used to convey how far one can see horizontally, which is crucial for pilots during takeoff, landing, and navigating through different airspace conditions. While other units, such as nautical miles or kilometers, might be relevant in different contexts or geographic regions, statute miles are the standard measurement adopted in aviation meteorological reports in the U.S.

Using feet is not appropriate for measuring visibility, as feet are typically utilized for altitude or elevation rather than distance. Thus, statute miles as the correct answer aligns with established aviation reporting practices and regulations.