What Is Visibility? Definition & Meaning in Aviation
Visibility is how far one can see horizontally in the prevailing weather, usually measured in metres or kilometres.
In plain language
Fog, mist, haze, smoke, dust and heavy rain reduce it. Airports have minimum visibility for landing and takeoff, and flights are delayed or diverted when it drops below them.
Example
During winter fog on the northern plains of Pakistan, visibility can fall to a few hundred metres.
Why it matters
Visibility is the single most common weather cause of delay on the Pakistani plains. When it falls below limits, flights wait; when it improves, they restart and a backlog clears slowly.