How do pilots know where turbulence is?

In this article · 6 sections

Three kinds of information
1. Turbulence forecasts
2. Official advisories
3. Reports from other pilots
What it means for you
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Three kinds of information

Pilots don't guess where the bumps are. They combine forecasts, official advisories and live reports, and keep updating the picture throughout the flight.

1. Turbulence forecasts

The US Aviation Weather Center publishes Graphical Turbulence Guidance (GTG), a forecast of where turbulence is expected and how strong, at levels from low altitude up to about 48,000 feet.² A related "nowcast" combines automatic turbulence calculations with real-time observations and is updated every 15 minutes.² The FAA describes that rapid update as helping pilots and dispatchers make tactical decisions about how to avoid turbulence.⁴

The forecast even accounts for the size of the airplane: the same patch of air counts as moderate turbulence for a light aircraft before it does for a heavy jet.² In other words, a big airliner feels the same air less.

2. Official advisories

Forecasters also issue in-flight advisories. A SIGMET describes weather expected to affect the safety of aircraft, such as severe turbulence; it's sent to all pilots in flight and is normally valid for four hours.¹ AIRMETs cover less severe conditions, and Convective SIGMETs cover thunderstorms.¹ Before departure, an airline's weather briefing must include turbulence forecasts and pilot reports, and dispatchers can mark expected bumps on the flight paperwork.³

3. Reports from other pilots

The most direct information comes from aircraft already flying the route. A PIREP (pilot weather report) tells controllers and forecasters what a crew actually found. Air traffic facilities are required to ask for reports whenever turbulence of moderate degree or greater is reported or forecast.¹ FAA guidance encourages crews to ask controllers about "the rides" when they switch frequencies, and to tell their airline about unexpected bumps so flights behind them can plan another route.³

What it means for you

When the captain says "we're expecting some bumps in about twenty minutes", this is where that comes from. Forecasts aren't perfect, and some turbulence still arrives without warning,⁴ which is why the seat belt advice never changes.

You can see a plain-English version of the same public forecasts for your route in My Flight and on our turbulence forecast page.

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Quick answers

Can pilots see turbulence on radar?

Weather radar shows precipitation, such as storms, which pilots avoid. Turbulence itself is air movement that normally can't be seen and can happen in clear skies, so pilots also rely on forecasts, official advisories and reports from other aircraft.

What is a PIREP?

A pilot weather report: a pilot telling air traffic control or a flight service station about conditions such as turbulence, icing or cloud. Air traffic facilities are required to ask for these reports when moderate or greater turbulence is reported or forecast.

What is a SIGMET?

An official US advisory describing weather expected to affect the safety of aircraft, such as severe turbulence. SIGMETs are issued as needed, are usually valid for 4 hours, and go to all pilots in flight.

Can I check the turbulence forecast for my flight?

Yes. The same public forecasts pilots use are published by the NWS Aviation Weather Center. My Flight summarises them for your route in plain English, without scores.

Sources

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Facts last checked against these sources: October 18, 2026.