Visibility is reported to the nearest mile when it falls within which range?

Visibility is reported to the nearest mile when it falls within the range of 3 to 15 miles. This standard allows for a more precise reporting of visibility conditions, which is essential for pilots, meteorologists, and other professionals who rely on accurate weather data.

When visibility is between 3 and 15 miles, it enables the observer to provide a clear and helpful measurement for safe navigation and flight operations. Outside of this range, visibility measurements are typically rounded to larger increments, which may not be as useful for operations requiring high precision.

For instance, visibility less than 3 miles tends to be reported in more specific increments, such as in fractions of miles or meters, especially in conditions of low visibility like fog, heavy rain, or snowfall. Comparatively, visibility above 15 miles is often less critical for aviation and can be reported in general terms since it indicates very favorable conditions. Therefore, the standard takes into account the need for detailed observations in the most relevant visibility range, balancing precision with practicality for various weather assessments.