How many sectors can the horizon circle be divided into when determining the prevailing visibility?

The horizon circle can be divided into eight sectors when determining the prevailing visibility. This division helps observers assess visibility conditions from multiple directions, offering a comprehensive evaluation of how far one can see in various sectors surrounding the observer.

Each of the eight sectors represents a distinct 45-degree segment of the horizon, allowing for a detailed analysis of visibility variations throughout the full 360 degrees. This method enables surface weather observers to accurately identify the direction from which the greatest visibility is observed, which is essential for reporting conditions that reflect the overall visibility rather than just localized phenomena.

If fewer sectors were used, the assessment might overlook significant variations in visibility that can occur due to factors like fog, rain, or obstructions in specific directions. Thus, the division into eight sectors is a standardized approach that enhances the accuracy and reliability of visibility reporting.