In Aviation Area Forecasts, how is visibility reported?

In Aviation Area Forecasts, visibility is reported in statute miles (SM). This is the standard unit of measurement used in aviation meteorology within the United States to indicate how far one can see horizontally. Statute miles provide a clear understanding for pilots and air traffic controllers, as they are familiar with this unit from other contexts, including aviation regulations and visual flight rules (VFR).

Using statute miles allows for consistency in reporting and helps ensure safety during flight operations. Other measurements like nautical miles or kilometers are not commonly used for reporting visibility in this context, and feet is used for altitude rather than horizontal visibility. Thus, the emphasis on statute miles is rooted in its widespread recognition and practicality in aviation communications.