San Francisco → Tokyo Turbulence Forecast
General route view · SFO → NRT
Light bumps
2 controlled bumps · 11:00
Light chop in places: uncomfortable, not dangerous. Your pilot already expects it.
→ What to do during turbulence: 4 stepsWhat is turbulence?
4 min · Learn
Turbulence from a pilot's view
4 min · Learn
Recognizing the flight panic loop
5 min · Learn
How dangerous is turbulence, really? 43 years of data
6 min · Learn
What's in the pilot briefing? What you don't see
5 min · Learn
What is the jet stream, and why do you feel it at cruise?
5 min · Learn
24 hours before your flight
5 min · Guides
What to do during turbulence: 4 steps
4 min · Guides
My first flight: a step-by-step guide for first-timers
7 min · Guides
General route view · SFO → NRT
2 controlled bumps · 11:00
Light chop in places: uncomfortable, not dangerous. Your pilot already expects it.
→ What to do during turbulence: 4 stepsTAKEOFF
Brief
First 20 min
CRUISE
Occasional
10h 20m
LANDING
Smooth
Last 20 min
San Francisco → Tokyo route, 8,228 km. Crosses the Great Plains, the North Atlantic, and the Appalachians. Winter jet stream may cause light bumps at cruise altitude; summer is typically smooth.
This forecast is calculated from the same ECMWF Open Data model airlines use (Ellrod TI2), and it only changes when the model refreshes on its own cycle. Refreshing the page every few minutes will not change the result.
Checking over and over tends to feed anxiety. A kinder rhythm is to look once the day before, once before you head to the airport, and then let it go. Being curious is very human; there is no need to be hard on yourself.
If the worry rises, breathe out slowly and feel your feet on the floor; even that much settles the body. All the techniques for fear of flying
San Francisco to Tokyo is about 8,227 km and usually takes around 11h in the air. Most of the track runs over open ground with few features to stir the air.
This track threads jet-stream latitudes, so in winter you may feel a few minutes of light, choppy air high up; summer usually rides calmer.
A flight this long spends hours at a high, smooth cruise. Even when one stretch is bumpy it is a small slice of the whole trip, and the aircraft treats it as routine.
Is turbulence dangerous?
Modern aircraft are engineered to handle even the heaviest turbulence. Turbulence is uncomfortable, but not a structural threat. Pilots can change altitude or routing to find calmer air.
Which times of day are smoothest?
Early morning and night flights tend to be smoother — thermal currents from solar heating can cause mild bumps on afternoon departures.
Why are there light bumps at cruise altitude?
At cruise altitude (around 10-12 km), wind shear from the jet stream can produce brief clear-air turbulence. It usually lasts a few minutes; the pilot turns on the seatbelt sign, sometimes adjusts routing.
How reliable is this forecast?
The forecast is computed from the winds of the same global weather model airlines use for flight planning. No weather forecast is 100%; treat this as direction, not a guarantee.
How do pilots know about turbulence ahead of time?
Before each flight, pilots get a wind map briefing, ICAO SIGMET (significant meteorological advisories), and pilot reports (PIREPs) from other aircraft. In flight, they stay in active contact with ATC and nearby aircraft.
Learn
What is turbulence?
4 min
Learn
Turbulence from a pilot's view
4 min
Learn
Recognizing the flight panic loop
5 min
Learn
How dangerous is turbulence, really? 43 years of data
6 min
Learn
What's in the pilot briefing? What you don't see
5 min
Learn
What is the jet stream, and why do you feel it at cruise?
5 min
Guides
24 hours before your flight
5 min
Guides
What to do during turbulence: 4 steps
4 min
Guides
My first flight: a step-by-step guide for first-timers
7 min
Data: global weather model (ECMWF) · Generated Wed 12:16