Route turbulence forecast
San Francisco → Tokyo
Turbulence forecast for flights from San Francisco International Airport (SFO) to Narita International Airport (NRT).
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Get a segment-by-segment turbulence forecast for any scheduled flight from SFO to NRT, with live wind and pilot reports.
Live status with real-time delays and cancellations.
What to expect on this route
Westbound (usually into prevailing winds) · Great-circle bearing -57°
Jet-stream exposure on this corridor is significant. Long mid-latitude legs mean clear-air turbulence is the dominant source of bumps, typically encountered at cruise altitude. The route crosses or passes near the Rocky Mountains, Japanese Alps, which can generate mountain-wave turbulence downwind when upper-level winds are strong. Westbound aircraft typically fly against the prevailing winds, adding flight time. Captains often pick altitudes that avoid the strongest headwinds, which can also mean picking cleaner-air altitudes.
- Mountain crossings
- Rocky Mountains · Japanese Alps
- Ocean / water segments
- North Pacific
Seasonal turbulence pattern
This corridor is most turbulent in the northern winter (Nov–Mar), when the jet stream is strongest and sits closer to the route. Wind flowing over the Rocky Mountains can generate mountain-wave turbulence that extends hundreds of kilometres downwind — most pronounced in the northern winter (Nov–Mar), when upper-level winds are strongest.
- Peak turbulence
- November–March (Northern Hemisphere winter)
- Typically calmest
- Late spring to early autumn (May–September)
SFO → NRT turbulence FAQ
Is the San Francisco to Tokyo flight usually bumpy?
Most of the 8,228 km route sits in the mid latitude band with high jet-stream exposure. Historically that means occasional clear-air turbulence at cruise altitude is normal, especially in winter. Mountain-wave effects near the Rocky Mountains add short bumpy stretches when upper-level winds are strong.
When is the best time to fly SFO to NRT for a smooth flight?
Statistically, Late spring to early autumn (May–September) sees the calmest conditions for this corridor. Within any season, morning departures see less convective (thunderstorm-driven) turbulence than afternoon flights.
How long is the flight from SFO to NRT?
Block time is usually around 10h 04m direct, cruising at approximately FL390 (39,000 ft). Actual duration varies with winds — tailwinds can shave 15–30 minutes, headwinds can add 30+ minutes on this westbound sector.
How accurate is Turbcast's forecast for this route?
We use live NOAA Aviation Weather Center pilot reports (PIREPs), SIGMETs and AIRMETs, layered with physics-based Ellrod and Richardson-number calculations from Open-Meteo pressure-level wind and temperature data. If a source is unavailable for a waypoint we show an em dash rather than invent a value.
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