What is prevailing visibility and how does it differ from point visibility?

• A. Prevailing visibility is the visibility at the aircraft's current location; point visibility is the average across the area.
• B. Prevailing visibility is the greatest distance seen in all directions across the area; point visibility is what’s observed at a single point.
• C. Prevailing visibility is the visibility reported by METAR; point visibility is the visibility reported by pilots.
• D. Prevailing visibility is only used in VFR; point visibility is used in IFR.

Answer: (B)

Prevailing visibility describes the area-wide visibility: the greatest horizontal distance you can see when looking in all directions across the area around the observation point during the reporting period. Point visibility, on the other hand, is the visibility observed at a single location, such as at the weather station or the aircraft’s position. These can differ when visibility varies across the area, so the prevailing value gives a representative picture for the region, while the point value reflects local conditions at one spot. For aviation reporting, this distinction matters because pilots need to know the overall visibility environment, not just what’s seen at a single point.