What Is a PIREP? How to Read and Give a Pilot Weather Report

A forecast says what should happen, and a METAR says what is happening on the ground. A PIREP says what a pilot actually found up there. This page decodes the FAA Aviation Weather Handbook's sample PIREP, gives the official turbulence and icing scales, and explains how to give a useful report. The rules come from the Handbook, the AIM, FAA Order JO 7110.10EE (the order Flight Service works under), and an NTSB safety alert on PIREPs [1][3][4][5].

What is a PIREP, and who uses it?

"Pilots can report any observation, good or bad, to assist other pilots with flight planning and preparation." [1, para. 24.5.1] The reports go into the weather distribution system for everyone [3, para. 7-1-18]. The NWS uses them "to verify or amend conditions contained in aviation forecast and advisories" [3, para. 7-1-18]. The NTSB puts it strongly: "A single PIREP can influence a weather forecaster’s decision to issue (or discontinue) a hazardous weather advisory, such as an AIRMET or a SIGMET, and/or amend its area." [4]

Air traffic facilities don't wait for volunteers. "FAA air traffic facilities are required to solicit PIREPs when the following conditions are reported or forecast: ceilings at or below 5,000 feet; visibility at or below 5 miles (surface or aloft); thunderstorms and related phenomena; icing of light degree or greater; turbulence of moderate degree or greater; wind shear and reported or forecast volcanic ash clouds." [3, para. 7-1-18] Flight Service's order adds braking action reports less than good and sulfur gases in the cabin [5, para. 8-1-2].

UA or UUA: routine or urgent?

"The two types of PIREPs are Urgent (UUA) and Routine (UA)." [1, para. 24.5.1.1] A report is urgent (UUA) when it contains [1, para. 24.5.1.1.1][5, para. 8-1-3]:

• Tornadoes, funnel clouds, or waterspouts.
• Severe or extreme turbulence, including clear air turbulence.
• Severe icing, or hail.
• Low-level wind shear within 2,000 ft of the surface, if airspeed changed 10 knots or more or the change wasn't reported.
• Volcanic ash clouds, or anything else the controller or specialist judges hazardous.

Everything else is routine (UA). Flight Service delivers urgent PIREPs to the ARTCC weather coordinator as soon as possible [5, para. 8-1-9].

How do you read a PIREP? A worked decode

After the message type, each element starts with a slash and a code, such as /OV for location [5, para. 8-1-9][3, para. 7-1-18]. Here is the Handbook's sample PIREP, transcribed exactly from Figure 24-5 of the FAA Aviation Weather Handbook [1, para. 24.5.1]. It is an official teaching example, not a live report. Hover, focus, or tap any field.

Scroll sideways to see the full line.

UA /OV APE230010/TM 1516/FL085/TP BE20
/SK BKN040-TOP065/WX FV03SM BR/TA M02
/WV 23008KT/TB LGT/IC TRACE RIME/RM TCU W

Official sample PIREP, FAA Aviation Weather Handbook (FAA-H-8083-28B), Figure 24-5, transcribed from the figure image [1, para. 24.5.1]. In the distributed report, a three-letter identifier for the nearest weather reporting location comes first [3, para. 7-1-18].

Field by field. "Handbook meaning" is quoted exactly from FAA Aviation Weather Handbook 24.5.1; "Plain English" is ours, with the rule behind it cited.

Read as a whole: at 1516 UTC, 10 NM southwest of the Appleton VOR at 8,500 ft MSL, a King Air 200 reported a broken layer from 4,000 to 6,500 ft, 3 miles visibility in mist, minus 2°C, wind 230 magnetic at 8 knots, light turbulence, trace rime ice, and towering cumulus to the west. For a pilot behind it, the useful parts are the tops, the temperature, and the ice.

A second example: an urgent PIREP

Scroll sideways to see the full line.

UUA/OV ANC240075/TM 2110/FL370/TP DC10/WX VA/RM VOLCANIC ERUPTION 2008Z MT
AUGUSTINE ASH 40S MOV SSE

Example from FAA Aviation Weather Handbook Section 24.5.1.12.8 [1, para. 24.5.1.12.8]. Not a live report.

The Handbook's decode: "Urgent PIREP, 240° at 75 NM from Anchorage International Airport, Anchorage, AK, 2110 UTC, FL370, a DC-10 reported volcanic ash", with the eruption time, the mountain, and the ash's position and movement in the remarks [1, para. 24.5.1.12.8]. "Volcanic ash alone is an Urgent PIREP."

How is turbulence intensity reported?

By how the aircraft reacts, judged by the pilot [1, para. 24.5.1.10]. The AIM's reporting criteria [3, para. 7-1-21]:

Add the duration: occasional means less than 1/3 of the time, intermittent 1/3 to 2/3, and continuous more than 2/3 [3, para. 7-1-21]. High-level turbulence, normally above 15,000 ft and away from cumuliform clouds, is reported as CAT [3, para. 7-1-21]. Turbulence reports should say whether you were in cloud or clear air, and the aircraft type [1, para. 24.5.1.10].

How is icing intensity reported?

The AIM defines four intensities by accretion rate and the pilot's response [3, para. 7-1-19]:

The scale is relative: "Severe icing is aircraft dependent, as are the other categories of icing intensity." [3, para. 7-1-19] Report the type too: rime, clear ice, or mixed ice [3, paras. 7-1-19 and 7-1-20], coded RIME, CLR, or MX [1, para. 24.5.1.11].

How do you give a PIREP?

"PIREPs should be given to the ground facility with which communications are established; i.e., FSS, ARTCC, or terminal ATC." [3, para. 7-1-18]

1. Fly first. Report when workload permits [4]. Flight Service specialists are told not to ask during hazardous weather or takeoff and landing, because "the pilot’s top priority is to keep control of the aircraft" [5, para. 8-1-2].
2. Say where and when. Give the location relative to a VOR or airport and the UTC time of the encounter, as precisely as you can [1, paras. 24.5.1.2 and 24.5.1.3][4].
3. Give altitude and aircraft type. Both are required, and essential for turbulence and icing [1, para. 24.5.1][3, para. 7-1-18].
4. Describe it in standard terms. Cloud bases and tops, flight visibility and weather, temperature, wind, turbulence with duration, and icing with type, using the scales above [3, para. 7-1-18]. Include the temperature with icing [1, para. 24.5.1.11].
5. For wind shear, give the airspeed change. "The recommended method for wind shear reporting is to state the loss or gain of airspeed and the altitudes at which it was encountered." Avoid "negative" or "positive" wind shear [3, para. 7-1-22].
6. Don't worry about format. "pilots should not be overly concerned with strict format or phraseology." The ground station will ask if it needs more [3, para. 7-1-18].
7. Report the good and the late. "Remember that PIREPs for null and light conditions, as well as conditions that are 'as forecasted,' are as important as reports of hazardous or unexpected weather." Reports filed after landing still help if the time and location are accurate. Electronic tools are another option, but for urgent hazards, radio to ATC likely spreads the word fastest [4].

Illustrative order for a radio report (not a real report): identification, "PIREP," location, time, altitude, aircraft type, then conditions. For example: Skyhawk 1234X, PIREP, over the Topeka VOR at 1510 Zulu, five thousand five hundred, Cessna 172, tops of the overcast five thousand, smooth, outside air temperature plus four.

Where can you see every PIREP field and code?

Source conflict, noted: FAA Order JO 7110.10EE lets specialists encode wind shear as plus or minus [5, para. 8-1-8], and the Handbook's example uses +/-15 KT [1, para. 24.5.1.12.1], while the AIM tells pilots to avoid "negative" and "positive" wind shear because such reports have been misread [3, para. 7-1-22]. This page follows the AIM for what pilots say: the airspeed gained or lost, and where.

Where do PIREPs mislead pilots?

• There are few of them. "Pilots submit relatively few PIREPs compared to overall traffic volume" [4]. No report is not the same as no hazard: "nor can a report of no icing assure the absence of icing conditions at a later time" [3, para. 7-1-20].
• Intensity depends on the airplane. Icing categories [3, para. 7-1-19] and wind shear [5, para. 8-1-8] are aircraft dependent. Moderate in a King Air may be worse in a light single; check /TP.
• Time and place can be off. The NTSB warns that time or location errors "greatly diminish its usefulness" [4].
• Heights are MSL. Don't compare PIREP tops directly with METAR cloud heights, which are above ground [1, paras. 24.4.3.9 and 24.5.1].

How do you use PIREPs in a go/no-go decision?

The decision is yours as pilot in command. A few habits:

• Filter by route, altitude, time, and type. Reports near your route and altitude, from the last hour or two, from aircraft like yours, matter most.
• Use them to check forecasts. Compare with G-AIRMETs and SIGMETs (advisories guide) and with airport METARs and TAFs (METAR guide, TAF guide).
• Plan your out. Tops and temperatures in PIREPs tell you whether climbing or descending gets you out of ice.
• Write it down. A FRAT records the hazards you found [6, ch. 3].

Where do PIREPs fit in a disciplined decision?

PlaneWX is decision support for general aviation pilots, built around one idea: "Fly like it's your job." Treat the weather decision the way a professional crew would, with the same process every time. That process is a loop: Brief, then FRAT, then Fly or Stay, then Debrief, with a Mentor if you want one. PIREPs feed the Brief. Here's how PlaneWX handles them, as described in the help center [7]:

• Brief: which PIREPs count. Reports from the last 2 hours, within a 50 to 75 NM corridor that scales with the route, and within 4,000 ft of your cruise altitude (Weather Decisions). Old PIREPs that won't persist to departure time don't reduce the score (How Scoring Works).
• Brief: turbulence. Turbulence PIREPs are normalized by aircraft weight class for GA, and each flight phase shows the worst of the model data, G-AIRMET Tango, and PIREPs. Corroborated PIREPs beyond your hard limit set the WX Score to 0% (Turbulence Analysis).
• Brief: tops and ice. In the Altitude Advisor, PIREPs with bases and tops are high-confidence data: "These are the only source of observed cloud tops." (Altitude Advisor) The FAA/NWS Current Icing Product that PlaneWX uses fuses icing PIREPs (Icing Analysis). In the final hour, a live fetch pulls PIREPs straight from the Aviation Weather Center (Auto-Refresh).
• FRAT. The flight risk assessment opens within 4 hours of departure, and your own ratings drive it (FRAT).
• Fly or Stay. "PlaneWX never recommends GO or NO-GO. You make the call as PIC." (The Risk Loop)
• Debrief. Self Debrief looks back at the flight, a natural moment to file the PIREP you didn't have time for. It is a PlaneWX Labs feature for Pro Plus (The Risk Loop).

The help center is plain about the limits: "PlaneWX is not a substitute for a complete, independent pre-flight weather briefing. Pull one from a source you already trust before you fly." (The Risk Loop)

See the PIREPs along your next route in a PlaneWX briefing, or read how PlaneWX weighs turbulence PIREPs. Related: icing analysis, the Altitude Advisor, and PlaneWX research on turbulence safety.

This page explains published FAA, NWS, and NTSB guidance. The PIREPs shown are official teaching examples from the FAA Aviation Weather Handbook, not live reports. Always get a current briefing before you fly.