PIREP
Also called: pilot report, pilot weather report
A PIREP, or pilot report, is a report of the actual weather an aircraft encounters in flight, made by the pilot or a crew member. PIREPs describe conditions such as turbulence, icing, and cloud layers at a stated location and altitude, which fills the gaps between ground stations with direct observations from the air.
Key Points
- A coded PIREP starts with the location or extent of the weather being reported.
- The aircraft type is included for turbulence and icing reports, because the same air affects a light aircraft and an airliner differently.
- PIREPs are observations, not forecasts. SIGMETs and AIRMETs are the advisories that warn of the same hazards ahead of time.
Related Terms
AIRMET
Airmen's Meteorological Information, an advisory for weather hazardous primarily to light aircraft including moderate turbulence, icing, and low visibility. AIRMETs are less severe than SIGMETs.
SIGMET
Significant Meteorological Information, an advisory for hazardous weather affecting all aircraft including severe turbulence, icing, volcanic ash, and thunderstorms. SIGMETs cover large areas and last up to 4 hours.
METAR
Meteorological Aerodrome Report, a standardized format for reporting current weather conditions at airports. METARs are issued hourly (or more frequently during significant changes) and include wind, visibility, clouds, temperature, and pressure.
TAF
Terminal Aerodrome Forecast, a weather forecast for the area within 5 miles of an airport. TAFs are issued every 6 hours and cover a 24-30 hour period, providing expected winds, visibility, clouds, and precipitation.
Ceiling
The height above ground of the lowest broken or overcast cloud layer, or vertical visibility into an obscuration. Scattered clouds do not form a ceiling. A ceiling below 1,000 feet falls in the IFR or LIFR weather category; legal flight and approach requirements depend on airspace, visibility, regulations, equipment, and pilot qualifications.
LIFR
LIFR, Low Instrument Flight Rules, is the lowest of the four aviation weather flight categories. It means a ceiling below 500 feet and/or visibility of less than 1 statute mile. Whichever of the two is lower sets the category. The categories above it, in order, are IFR, MVFR, and VFR.
PIREP: Guides and Explainers
These explainers connect this definition to real-world forecasting and decision-making.
Weather Education
GFS vs HRRR vs NAM: Which Weather Model Should You Trust?
Learn the differences between GFS, HRRR, NAM, and the Euro model. Understand which forecast model to trust for different situations and how weather enthusiasts can interpret model data.
Guides
METAR Codes Decoded: A Pilot's Guide to Reading Aviation Weather
Learn how to read and decode METAR weather reports. Understand aviation weather codes, visibility, cloud layers, and all the abbreviations pilots need to know.
Helpful Tools and Hubs
Use these pages to apply the concept, compare conditions, or follow related weather workflows.
Feature
Aviation Weather
Track METARs, TAFs, and airport conditions in a pilot-friendly layout.
Use Case
Weather App for Pilots
Follow the aviation workflow for METARs, TAFs, ceilings, and crosswinds.
Tool
Crosswind Calculator
Calculate headwind and crosswind components for any runway and wind combination.
Tool
Flight Rule Calculator
Classify VFR, MVFR, IFR, and LIFR conditions from ceiling and visibility.
Sources
Explore Other Terms
Liquefaction
A process in which water-saturated, loosely packed soil temporarily behaves like a liquid during strong shaking and loses its ability to bear weight. It can tilt or sink buildings, float buried tanks and pipes upward, and cause the ground to crack and spread sideways. Reclaimed land, river deltas, and sandy fill are especially vulnerable.
Tornado
A tornado is a violently rotating column of air in contact with the ground, extending from a thunderstorm. Tornadoes are rated from EF0 to EF5 on the Enhanced Fujita scale by the damage they cause. Most last less than 10 minutes, but the strongest can stay on the ground for more than an hour.
Thundersnow
A rare phenomenon where thunder and lightning occur during a snowstorm. Thundersnow typically happens in intense winter storms and is often associated with heavy snowfall rates of 2-4 inches per hour.
Heat Index
The heat index is how hot it feels when relative humidity is combined with the air temperature. Humid air slows the evaporation of sweat, so the body cools less efficiently and feels hotter than the thermometer reads. At 100°F with 55% relative humidity, the heat index is 124°F.
Velocity
Doppler radar measurement of how fast precipitation is moving toward or away from the radar. Velocity data reveals wind patterns, rotation in thunderstorms, and potential tornado signatures that reflectivity alone cannot show.
Probability of Precipitation
Probability of precipitation (PoP) is the chance that a given point receives measurable precipitation, at least 0.01 inch, during the forecast period. A 40% chance of rain means a 4 in 10 chance of at least 0.01 inch at your location. It does not mean rain over 40% of the area or for 40% of the time.
Browse by Category
In the WeatherAI App
WeatherAI shows PIREPs on the map for Standard and Pro subscribers. WeatherAI is not an FAA-approved flight-planning product.
Availability, coverage, update frequency, and alert delivery vary by data source, region, subscription plan, device permissions, and service conditions.