Calm guide
What turbulence feels like: the Cup Scale
Most turbulence feels like a car on a gravel road: the coffee ripples and settles again. Stronger bumps make you hold your drink and pause the service, and the rare firm patches are why the seatbelt sign exists. All of them usually pass within minutes.
Turbulence is simply air that isn't moving smoothly. An aircraft flying through it rises and falls a little, the way a boat moves on small waves. Pilots describe it with official categories, light, moderate, severe, but those words don't tell a passenger much. So we use a cup of coffee.
The Cup Scale
| Level | What you see | What it feels like |
|---|---|---|
| Smooth | The coffee stays still. | You forget you're flying. |
| Ripples | The coffee ripples. | Light, uneven bumps. Totally normal; the service usually carries on. |
| Bumpy | You hold your drink. | Noticeable jolts; the crew may pause the service and ask you to sit. |
| Seatbelt on | Belt fastened, cup down. | Firmer bumps. Stay seated with your belt fastened; it usually passes in minutes. |
The pilot categories line up roughly like this: light turbulence is our Ripples, moderate is Bumpy, and the firmest end of moderate and beyond is Seatbelt on. In the FAA's reporting criteria, light turbulence means a slight strain against the seat belt, with walking and food service still possible; moderate means a definite strain against the belt, with walking and food service difficult, while the aircraft stays in positive control.
Why the same flight can feel different to two people
Where you sit matters: the back of the cabin moves more than the front and middle. So does what you expect. A bump you saw coming feels smaller than one that surprises you. That's the reason we show where and when the bumps should be: when the coffee ripples over the Rockies right on time, it's just the forecast coming true.
What the crew is doing
When pilots expect bumps, they turn on the seatbelt sign early, slow to the recommended speed for rough air, and use reports from other pilots, which the FAA calls the best source of information on clear-air turbulence, to find smoother heights or routes. The ripples you feel are usually a short part of the trip.
How we use it in our forecast
Every Turbulence Radar forecast is written on this scale: a share of the flight that looks Smooth, and for the rest, the minutes of Ripples, Bumpy or Seatbelt on, with the place and the time into the flight. You can check your flight up to 48 hours before departure.
Questions people ask
Is light turbulence normal?
Yes. Light turbulence is part of almost every flight. It feels like a slight, uneven rocking and nothing in the cabin moves around.
How long does turbulence last?
Usually a few minutes. Pilots often change height or route to find smoother air, and our forecasts show how long each bumpy part of your flight is likely to last.
Why does the crew stop the drinks service?
When the ride gets bumpier, hot drinks and trolleys are harder to handle safely, so the crew sits down. It is a precaution, not a sign that something is wrong.
Sources
We write these guides for passengers, from official and peer-reviewed sources. They are not medical advice and not for flight operations. How our forecast works.