What does VV represent in aviation weather?

In aviation weather, VV specifically indicates "vertically visibility," which refers to the vertical extent of visibility through a layer of cloud or obscuration at the surface. When you see VV in meteorological reports or weather observations, it indicates that the sky is completely obscured by clouds or other phenomena at the surface. The term "8/8 at surface" signifies that the entire sky is covered, leading to a condition of total obscuration from the observer's perspective, making it impossible to see the natural skyline or any celestial bodies. This information is vital for pilots, as it directly impacts flight operations, particularly regarding take-offs and landings, by influencing decisions on whether a route can be flown safely given visibility conditions.