When a METAR report states visibility is between two measurements, what does that imply?

When a METAR report indicates that visibility is between two measurements, it means that visibility is variable and can fluctuate between those two specified mileages. This situation is often caused by weather conditions that can change rapidly, such as fog, rain, haze, or other atmospheric phenomena that can impact visibility.

Since visibility can differ greatly even within short distances, the report provides a range to inform pilots and other users of the report about the potential for varied visibility conditions within that range. This information is crucial for flight planning and safety, as pilots need to be aware of the changing visibility that could affect their operations. Understanding this variability helps in assessing potential challenges related to takeoff, landing, and navigation.