What is the prevailing visibility if observed values are N 3, NE 2 1/2, E 1, SE 3/4, S 2, SW 3 1/2, W 4, NW 2 3/4?

To determine the prevailing visibility, it is essential to analyze the visibility observations provided from different directions. The prevailing visibility represents the distance that can be seen clearly in the atmosphere, which is calculated by identifying the most frequently occurring visibility value from all observations.

In this case, the observations indicate varying visibility from multiple compass directions: North (3), Northeast (2.5), East (1), Southeast (0.75), South (2), Southwest (3.5), West (4), and Northwest (2.75). To find the prevailing visibility, we look for the visibility value that appears most commonly or is the highest value in terms of distance that contributes to the overall average.

After organizing the given values, we can observe that the value of 2.75 (from the Northwest observation) stands out by being the most representative of the general conditions, falling short of a full 3 miles but exceeding 2.5 miles, thereby making it the prevailing visibility measure.

Choosing 2.75 miles aligns with the common practice of determining visibility in meteorological reporting, where conversions from fractions to decimals are acceptable, thus placing it definitively in the range where 2.75 miles (or 2 3/4 statute miles) can be