Definition
On a surface weather map, the small open circle plotted at the geographic position of a weather reporting station. The amount of the circle that is filled in indicates the sky cover (cloud coverage) observed at that station, and surrounding symbols and numbers report wind, temperature, dew point, pressure, and other weather elements.
Plain English
It is the little circle on a weather map that marks where a weather station is located. How much of the circle is shaded shows how cloudy the sky is at that station.
Context Anchor
Seen on surface weather maps and station plots in FAA weather study materials.
Derivation
“Station” means a fixed reporting place, “location” means where it is, and “circle” describes the symbol used on the map. Together, the phrase means the circle that marks the fixed weather reporting place.
Why Pilots Care
Allows a pilot to quickly identify which weather observations apply to a specific point along the planned route.
Analogy
It works like a map pin: the circle marks the place, and the information around it tells you what is happening there.
Intuition Check
Do not read this as a circle showing an area around the station. It marks the station’s exact plotted position on the weather map.
Example Sentence 1
Looking at the surface chart, the pilot found the station location circle for Denver and saw it was fully shaded, indicating overcast skies.
Example Sentence 2
Pilots scan the station location circles first to find the nearest reporting station before interpreting the surrounding wind and cloud data.