Definition
A contraction used in aviation weather reports and forecasts (such as METARs and TAFs) to indicate that prevailing visibility is greater than 6 statute miles. The 'P' stands for 'plus,' meaning 'more than,' and 6SM is the maximum reported value in U.S. surface visibility coding.
Plain English
The visibility is better than 6 miles. Forecasters don't bother giving an exact figure beyond that — anything above 6 miles is just reported as P6SM.
Context Anchor
Seen in the visibility part of TAF and METAR weather reports.
Derivation
The 'P' is shorthand for 'plus' (more than), and 'SM' stands for 'statute miles' — the standard unit of visibility in U.S. weather reports. Statute miles are the everyday land miles (5,280 feet), not nautical miles.
Why Pilots Care
Tells the pilot that visibility is unrestricted and no weather phenomena are limiting sight distance.
Grounding Statement
P6SM does not mean unlimited visibility; it only means the forecast visibility is above 6 statute miles.
Intuition Check
Do not read the P as “poor” or “probability.” In this code, P means “greater than.”
Example Sentence 1
The TAF showed P6SM with a few clouds at 5,000 feet, so visibility was clearly not going to be a problem for the cross-country flight.
Example Sentence 2
With P6SM forecast, the approach proceeded under visual conditions without any visibility concerns.