Definition
A report of actual weather conditions encountered in flight, made by a pilot to a Flight Service Station, air traffic controller, or other ground facility. PIREPs include items such as location, time, altitude, sky conditions, visibility, turbulence, icing, and wind, and are passed on to other pilots and weather services to give a real-time picture of conditions aloft.
Plain English
A short report a pilot makes by radio describing the actual weather they are flying through, so that controllers, weather briefers, and other pilots know what conditions are really like up there.
Context Anchor
You will see PIREPs in weather briefings, aviation weather displays, and in flight when pilots share current weather conditions along a route.
Derivation
Short for 'pilot report.' The term is built from the two words it abbreviates and is pronounced 'pie-rep' on the radio.
Why Pilots Care
Supplies real-time observations that forecasts cannot provide, helping pilots avoid unexpected hazards.
Intuition Check
A PIREP is not a forecast. It is a real observation from a pilot who actually encountered the conditions.
Example Sentence 1
Climbing through 6,000 feet, the pilot gave a PIREP reporting light rime icing and tops at 8,500.
Example Sentence 2
Flight service updated the area briefing after receiving the PIREP about moderate turbulence.