What does the term "V" indicate in METAR visibility reporting?

In METAR visibility reporting, the term "V" denotes variable visibility, which indicates that visibility is not constant but fluctuates owing to changing conditions. For instance, pilots need to be aware that visibility may shift due to factors like weather changes, obstructions, or the presence of fog in certain areas as they approach or depart from an airport. This term serves as an important alert for aviation operations, as variable visibility may impact flight safety and takeoff or landing procedures.

The other options do not accurately capture the meaning of "V." For example, "very poor visibility" and "visibility has improved" convey specific qualitative assessments that are not represented by the abbreviation "V." Similarly, "visibility is clear" does not apply here, as "clear" is a qualitative term and not indicated by the letter "V" in METAR reports. Thus, understanding that "V" signifies variable visibility helps aviation professionals assess and adapt to changing conditions effectively.