Pilot turbulence reports (PIREPs): what they are and how to read them calmly
Pilots report the turbulence they meet so the planes behind them can avoid it. Learn what a PIREP is, how to read light, moderate and severe reports, where to see them, and why they make your flight smoother.
If you've ever searched for turbulence before a flight, you've probably come across PIREPs: pilot reports. They can look alarming at first, a map full of colored triangles and codes like MOD TURB. In reality they are one of the most reassuring things in aviation: a constant, shared conversation between pilots about where the air is smooth and where it isn't, so the planes behind them can choose the calm route.
Practical answer
A PIREP (pilot weather report) is a short message a pilot sends about the weather they actually meet, including turbulence: where, at what altitude, in what type of aircraft, and how strong. Air traffic control and weather services pass these reports on to other crews, who use them to pick a smoother altitude or route. Most turbulence reports you'll see are light or moderate, levels that mean bumpy and uncomfortable, not dangerous for the aircraft. The reports exist so that pilots can avoid bumps, which is why seeing many of them is a sign the system is working.
What a pilot report is
The US Federal Aviation Administration describes PIREPs in its Aeronautical Information Manual (AIM, chapter 7) as reports pilots make of the weather they encounter in flight: turbulence, icing, cloud tops, winds and more. Controllers actively ask for them, and pilots share them on the radio as "ride reports".
A typical conversation on the frequency sounds something like this: one crew asks the controller how the ride is at their planned altitude, and the controller answers with what aircraft ahead have reported, for example light chop at one level and smooth air a few thousand feet higher. The crew then asks to climb or descend. Passengers rarely notice any of this. They only notice that the flight got smoother.
There are two kinds of PIREP:
- Routine reports (coded UA): the everyday ones, mostly light or moderate turbulence.
- Urgent reports (coded UUA): used for hazardous conditions such as severe or extreme turbulence, so they reach other crews and forecasters quickly.
How to read a turbulence report
A coded PIREP can look like this (a made-up example in the standard format):
UA /OV ABC090030 /TM 1745 /FL350 /TP B738 /TB LGT-MOD CHOP
Read piece by piece:
| Code | Meaning | In the example |
|---|---|---|
| UA | Routine report (UUA = urgent) | Routine |
| /OV | Location, often from a navigation beacon | 30 miles east of a beacon |
| /TM | Time, in UTC | 17:45 UTC |
| /FL | Altitude in hundreds of feet | 35,000 feet |
| /TP | Aircraft type | A Boeing 737-800 |
| /TB | Turbulence intensity and type | Light to moderate chop |
The two fields that matter most for a passenger are the aircraft type and the intensity.
Why the aircraft type matters
The same patch of air feels very different in a small propeller plane and in a large jet. The FAA's turbulence reporting guidance asks pilots to include their aircraft type for exactly this reason. A "moderate" report from a small regional aircraft may be a gentle ride in a wide-body airliner. When you look at reports, focus on those from aircraft similar to yours.
What the intensity levels mean
The AIM gives pilots shared definitions, based on how the aircraft and the people inside it react. In plain words:
- Light chop: slight, rapid, rhythmic bumpiness. The plane stays on its altitude and heading. Your drink ripples.
- Light turbulence: brief, slight changes in altitude or attitude. You may feel a little pull against your seatbelt. Meal service usually continues.
- Moderate: firmer bumps. You clearly feel your seatbelt, loose objects can move, and walking and serving food become difficult. The aircraft stays in positive control at all times.
- Severe: large, abrupt changes. People are pushed hard against their belts and anything loose is thrown around. This is rare, it's what pilots work hardest to avoid, and it's the level where being buckled in matters most.
- Extreme: very rare, and the reason forecasters and pilots share reports so quickly.
"Chop" describes rhythmic bumpiness without real changes in altitude. "Turbulence" means the aircraft is actually moved up, down or sideways. Most of what passengers call turbulence on a normal flight is light chop or light turbulence.
Where you can see pilot reports
In the United States, NOAA's Aviation Weather Center (aviationweather.gov) publishes recent PIREPs on a public map, along with turbulence advisories:
- AIRMET Tango: an advisory for moderate turbulence over an area.
- SIGMET: an advisory for severe turbulence (among other hazards).
Many airlines also share automated turbulence data. Some aircraft measure the bumpiness themselves and send it every few minutes, without anyone pressing a button. IATA, the international airline association, runs a program called Turbulence Aware that pools this data between participating airlines, so crews get a live, objective picture rather than only spoken reports.
Pilot reports are written for pilots, so they can be hard to read. If you'd rather see a calm, passenger-friendly picture of your own route, try our free turbulence forecast: enter your airports and date and it shows where bumps are likely, minute by minute.
Why lots of reports is good news
It's easy to look at a map covered in turbulence reports and feel your stomach drop. Here's another way to see it:
- Every report is a warning shared in advance. The crew on your flight will know about that bumpy spot long before they reach it.
- Pilots change altitude to avoid it. Asking for a smoother level is one of the most common requests controllers hear on long flights.
- Reports are snapshots. Turbulence moves and fades. A report from an hour ago at another altitude may have nothing to do with your ride.
- The aircraft is built for it. Airliners are certified to carry loads well beyond what turbulence produces. Read more in Is turbulence dangerous?
The one thing reports change for you as a passenger: if your crew turns on the seatbelt sign, it's often because of a report from the aircraft ahead. Buckle up and know they are simply being careful.
Should you check PIREPs before your flight?
That depends on you. Some nervous flyers find it calming to know what to expect; others find raw reports make them more anxious, because they are full of codes and missing context. A few gentle guidelines if you do look:
- Check the day before and on the morning of your flight, not every hour.
- Look for reports from similar aircraft, at cruising altitudes (above about 30,000 feet).
- Remember that "moderate" means uncomfortable, not unsafe.
- Close the tab once you know the general picture. Your crew will keep watching for you.
If turbulence is the heart of your fear, it helps to understand where it comes from: What causes turbulence and Clear-air turbulence explain it step by step. And if you'll be flying long-haul, see Turbulence on a long-haul flight.
Frequently asked questions
What does PIREP stand for?
PIREP is short for pilot report, more precisely a pilot weather report. It's a short message from a pilot about the conditions they actually met in flight, such as turbulence, icing or cloud tops.
Can passengers see pilot turbulence reports?
Yes. In the US, recent PIREPs are published on NOAA's Aviation Weather Center website, aviationweather.gov. They are written in pilot shorthand, so a passenger tool such as our turbulence forecast is usually easier to read.
What is the difference between moderate and severe turbulence?
In moderate turbulence you clearly feel your seatbelt and walking becomes difficult, but the aircraft stays in positive control. In severe turbulence the changes are large and abrupt and anything loose is thrown around. Severe turbulence is rare, and it's the level pilots work hardest to avoid using forecasts and reports.
Do pilots really change altitude because of turbulence reports?
Yes. Asking air traffic control for a smoother altitude after hearing ride reports from aircraft ahead is routine, especially on long flights. It's usually the reason the bumps stop soon after they start.
Is a turbulence report a reason to cancel my flight?
No. Flights operate every day through areas with reports of light and moderate turbulence. Pilots plan around them. The most useful thing you can do is keep your seatbelt fastened whenever you are seated.
