Definition 1 of 2
Definition
The prevailing visibility reported from the air traffic control tower cab, observed by the controller from tower height rather than from ground level. When an official weather observer is located in the tower, this value becomes the official visibility for the airport whenever it is lower than the surface visibility reported from the ground.
Plain English
How far the controller in the tower can see, looking out from up in the tower cab. Because the tower is high up, this view can differ from what a person sees standing on the airport surface.
Context Anchor
Seen in airport weather reports and instrument procedure discussions when the view from the control tower is reported separately from the main surface visibility.
Why Pilots Care
Can allow continuation of an approach or departure when the tower sees better conditions than the automated surface report.
Grounding Statement
Picture someone looking across the airport from the control tower and reporting how far they can clearly see from that elevated position.
Intuition Check
Do not read tower visibility as just “visibility near a tower” or a casual controller estimate. In this context, it is an official visibility observation made from the airport control tower.
Example Sentence 1
ATIS reported surface visibility one mile and tower visibility three-quarters of a mile, so the lower value applied to our approach minimums.
Example Sentence 2
With tower visibility reported at one mile, the flight continued under the lower minimums allowed for that observation.