Route turbulence forecast
London → San Francisco
Turbulence forecast for flights from London Heathrow Airport (LHR) to San Francisco International Airport (SFO).
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Get a segment-by-segment turbulence forecast for any scheduled flight from LHR to SFO, with live wind and pilot reports.
Live status with real-time delays and cancellations.
What to expect on this route
Northbound · Great-circle bearing -44°
The route crosses mid-latitudes where the polar jet can influence flight conditions, though exposure is shorter than on genuine long-haul crossings. The route crosses or passes near the Greenland ice cap, Rocky Mountains, which can generate mountain-wave turbulence downwind when upper-level winds are strong.
- Mountain crossings
- Greenland ice cap · Rocky Mountains
- Ocean / water segments
- North Atlantic · North Pacific
Seasonal turbulence pattern
The oceanic track sees its strongest jet-stream activity in the northern winter (Nov–Mar), when winds aloft are fastest and clear-air turbulence is more frequent. 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 Greenland ice cap 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)
LHR → SFO turbulence FAQ
Is the London to San Francisco flight usually bumpy?
Most of the 8,616 km route sits in the subpolar band with moderate jet-stream exposure. Historically that means occasional clear-air turbulence at cruise altitude is normal, especially in winter. Mountain-wave effects near the Greenland ice cap add short bumpy stretches when upper-level winds are strong.
When is the best time to fly LHR to SFO 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 LHR to SFO?
Block time is usually around 10h 31m 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 northbound 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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Articles
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