What does "VIS S 1 W 1/4" indicate in METAR coding?

The interpretation of "VIS S 1 W 1/4" in METAR coding indicates visibility and the direction it is measured from, specifically south and west, as well as the distance of visibility. In this case, "VIS" stands for visibility, "S" refers to south, and "W" refers to west. The distances provided, "1" and "1/4," denote the visibility in statute miles; hence, "1" represents one mile and "1/4" represents a quarter of a mile.

This coding is typical in METAR reports to convey crucial visibility information to pilots and air traffic controllers. Understanding directions is critical in aviation since visibility can vary significantly in different directions, affecting flight operations and safety.

Although the other options may mention similar terms, they do not correctly interpret the specific METAR coding format or fail to represent the full structure indicated within the report accurately. Thus, recognizing that "VIS S 1 W 1/4" specifically describes visibility at one mile towards the south and a quarter-mile towards the west is essential for accurate communication in aviation weather reporting.