The PIREP, the Only Weather Report Written by Someone Who Was Actually There, and Why Student Pilots Almost Never Think to Ask for One

A Pilot Report, or PIREP, is the only aviation weather product generated by someone physically present in the airspace you are about to fly through. Unlike forecasts and models, PIREPs deliver real-time observations of temperature, turbulence, icing, and visibility from pilots who just flew your route. Learning to read, request, and file them is one of the highest-value weather skills a student pilot can develop.

What Is a PIREP and Why Does It Matter?

The FAA abbreviates routine Pilot Reports as UA and urgent ones as UUA. What they represent is straightforward: a pilot was in that airspace, at that altitude, at that time, and reported what they found.

That distinction matters. A forecast tells you what the atmosphere is expected to do. A PIREP tells you what the atmosphere is doing. Temperature, cloud layers, turbulence, icing, visibility - these are real conditions, not model output.

Many student pilots treat PIREPs as background noise in their briefings. That is a mistake. No other weather product in your preflight package was produced by a human being who was physically there.

How Do You Read a PIREP?

PIREPs use a structured format with labeled fields separated by forward slashes. Each field opens with a two-letter identifier. Once you know what those identifiers mean, the format opens up quickly.

OV - Location. A station identifier followed by a direction and distance. OV ABC090025 means the report was taken near ABC airport on the 090-degree radial, 25 nautical miles out - due east of the airport, 25 miles.

TM - Time. Expressed in Coordinated Universal Time as four digits. 1430 is 1430 Zulu.

FL - Altitude. Expressed in hundreds of feet. FL065 is 6,500 feet. FL150 is 15,000 feet. Below 18,000 feet this is simply altitude in hundreds - not a true flight level.

TP - Aircraft type. This field matters for calibration. Light turbulence in a Boeing 737 is a very different data point than light turbulence in a Cessna 172. A large transport aircraft may call something light that would have your trainer bouncing. Use the TP field to adjust your interpretation of reported conditions.

SK - Sky condition. Cloud layers from the pilot’s perspective, including tops if the pilot was above the clouds.

WX - Flight visibility and weather. Visibility in miles, with any weather encountered.

TA - Outside air temperature. In degrees Celsius. This is critical for icing assessment. You cannot have structural icing without visible moisture and temperatures at or below freezing. The temperature in a PIREP is one of the most reliable data points you have for evaluating icing risk along your route.

WV - Wind direction and velocity.

TB - Turbulence. The scale is standardized across the entire reporting system:

• Smooth - no turbulence
• Light - slight, erratic changes in altitude and attitude; passengers feel a slight strain against seat belts
• Moderate - similar to light but greater intensity; unsecured objects get displaced; passengers feel a definite strain
• Severe - abrupt changes in altitude and attitude, large variations in indicated airspeed; aircraft may be momentarily out of control
• Extreme - aircraft violently tossed, practically impossible to control; structural damage possible

Duration matters as much as intensity. A pilot reporting light chop for 10 miles is describing something very different from moderate turbulence continuous for 40 miles. The word continuous is significant. Continuous moderate turbulence through 40 miles of airspace is a go/no-go factor.

IC - Icing. Intensity scale: trace, light, moderate, and severe. Type: rime, clear, or mixed.

Rime ice forms when small supercooled water droplets freeze instantly on contact with the aircraft. Clear ice forms from larger droplets that flow back before freezing. Clear ice is denser, sticks harder, and is more dangerous - it disrupts airflow more aggressively and is harder to remove. A PIREP reporting clear ice at any intensity level is a more serious data point than rime at the same intensity.

RM - Remarks. Free text, and often the most useful part of the entire report. A pilot can note icing in clouds, smooth on top at 8,500, or ceiling lower than the TAF suggests - context that coded fields can never quite capture.

What Does a Complete PIREP Look Like?

Here is a full example:

UA /OV MOB090040 /TM 1430 /FL065 /TP C172 /SK BKN050 OVC090 /TA -2 /TB LGTCHOP /RM ICG IN CLDS

Working through it: this is a routine report filed 40 nautical miles east of Mobile, Alabama at 1430 Zulu. The aircraft was a Cessna 172 at 6,500 feet. Sky was broken at 5,000, overcast at 9,000. Outside air temperature was minus 2°C. Turbulence was light chop. The remark: icing in clouds.

That last field changes everything. Light chop is manageable. But icing in clouds at 6,500 feet, in a Cessna 172, at below-freezing temperatures is a serious data point. That pilot flew through conditions you do not want to replicate unless your aircraft is certified for flight into known icing.

Where Do You Find PIREPs Before and During a Flight?

Preflight - 1800wxbrief.com: When you call for a standard briefing, the specialist pulls PIREPs from along your planned route. You can also ask specifically for PIREPs within a certain geographic area or altitude band.

Online - Aviation Weather Center: aviationweather.gov has a dedicated PIREP map display with filters for altitude, aircraft category, weather type, and time window. Geographic gaps in coverage are themselves meaningful - if nobody has recently flown your corridor, you are working from forecast data alone.

In flight - ATC: You can request PIREPs from any facility you are working with. Ask: Request any PIREPs on route. Controllers frequently have them and can pass them along. If you encounter something significant yourself, you can file a PIREP right there on frequency - the controller relays it to other aircraft and enters it into the system.

What Are the Limitations of PIREPs?

PIREPs are valuable, but their limits are part of using them correctly.

Coverage gaps. PIREPs only exist where pilots have recently flown. A route crossing a mountain range at 6 a.m. with light traffic may have no PIREPs at the altitudes you need. That is not a reason to cancel - it is a reason to be conservative and to file your own report when you come through.

Age. The FAA considers a PIREP valid for one hour from filing. Weather changes. A light chop report from 90 minutes ago during a rapidly evolving weather system may not reflect current conditions. Always check the time stamp.

Altitude specificity. A PIREP at 8,000 feet tells you about 8,000 feet. Turbulence and icing can vary significantly over just a few hundred feet of altitude change. When you use PIREPs to pick a cruising altitude, you are interpolating between data points, not reading a continuous survey of the atmosphere.

Subjectivity. The same air can feel different to different pilots in different airplanes. Use the TP field to calibrate intensity reports relative to what you are flying.

How Do You File a PIREP After Landing?

PIREPs are a shared resource. The system works because pilots contribute to it.

If you encountered icing at 7,500 feet, file it. If the ride was smooth above a broken layer when forecasters predicted rough air, file it. If the actual ceiling was lower than the TAF predicted, file it. That information has direct value to a pilot making a go/no-go decision right now.

Where to file:

• Online form at aviationweather.gov
• Verbally via 1-800-WX-BRIEF after landing
• Through your electronic flight bag application - many have PIREP filing built in, and some allow filing while still airborne

You do not need to report every field. Location, time, altitude, aircraft type, and the specific phenomenon you encountered is enough to be useful. It takes about 60 seconds.

What Do Examiners Expect on the Private Pilot Checkride?

The Airman Certification Standards for private pilot require you to demonstrate that you can gather and interpret weather information, and that explicitly includes Pilot Reports.

During the oral exam, you may be shown a PIREP and asked to decode it. Know your two-letter field identifiers. Know the turbulence and icing reporting scales. Know how to assess the age and location of a report relative to your planned route.

You may also be asked how you would incorporate PIREPs into a go/no-go decision. If the forecast calls for icing and no PIREPs confirm it on your route, that is useful information - but it may mean nobody has recently flown that corridor, not that the icing isn’t there. If three PIREPs from the last hour all report moderate turbulence where the forecast says light, trust the PIREPs. That is ground truth.

The examiner is not looking for a perfect formula. They want to see disciplined reasoning from a pilot who understands what each product tells them and - just as importantly - what it cannot.

Key Takeaways

• A PIREP is the only aviation weather product produced by a pilot physically present in that airspace - treat it as ground truth, not background noise.
• The TP (aircraft type) field is essential for calibrating reported turbulence and icing intensity to your own aircraft.
• The FAA considers a PIREP valid for one hour - always check the time stamp, especially in rapidly changing weather.
• When the official forecast and multiple recent PIREPs disagree, trust the PIREPs; they reflect actual conditions, not model predictions.
• Filing a PIREP after landing takes about 60 seconds and directly benefits the next pilot on your route.