When is the Seattle to London route most turbulent?

Check the monthly chart for exact patterns. Transatlantic and mountain routes are typically roughest in winter (Dec–Mar). Tropical routes peak during monsoon season.

SEA to LHR Turbulence Forecast

Q: Is the Seattle to London flight turbulent?

The SEA–LHR route typically experiences light turbulence.

Q: Which seat is smoothest on SEA to LHR?

Wing seats are smoothest. On a Boeing 757 · Airbus A330, that's rows 14–24. Avoid the rear of the aircraft.

Q: How long is the flight from SEA to LHR?

The SEA to LHR flight takes approximately 9h 40m, covering 4,785 miles at 37,000 feet.

Is the Seattle to London flight turbulent? Live forecast & historical patterns.

Live forecast

SEA

→

LHR

Seattle · London · 9h 40m

42.4

Turb Score

9h 40m

Duration

4,158 nm

Distance

37,000 ft

Cruise Alt.

Light

Typical

⚠️ Light turbulence today

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Typical turbulence along the route

Historical average pattern for SEA–LHR

0h1h2h3h4h5h6h9h 40m

Smooth

Light

Moderate

Heavy

About the SEA–LHR route

The Seattle to London route crosses the North Atlantic, where the jet stream is the primary source of turbulence. Flying at 37,000 feet, the aircraft encounters the strongest bumps roughly 2–5 hours into the flight. This is clear-air turbulence — no clouds, no visual warning — which makes a pre-flight forecast especially valuable.

The route is served by American Airlines, United, Delta on Boeing 757 · Airbus A330 aircraft, with flights typically cruising at 37,000 feet over a distance of 4,785 miles (4,158 nautical miles).

💡 Tip: Turbulence peaks mid-flight over the Atlantic. First and last hour are usually smooth.

Seattle to London Flight Time

How long is the flight from SEA to LHR?

9h 40m

Flight Time

4,785 mi

Distance

37,000 ft

Cruising Altitude

Boeing 757

Aircraft

The Seattle (SEA) to London (LHR) flight takes approximately 9h 40m, covering 4,785 miles (4,158 nautical miles) at 37,000 feet. The route is operated by American Airlines, United, Delta. Return flights (LHR to SEA) take a similar time, though westbound transatlantic and transpacific routes are typically 30–60 minutes longer due to headwinds.

Turbulence levels on SEA–LHR

What to expect at each phase of the flight

SmoothDeparture & arrival — climb and descent phases are generally calm

LightMinor bumps — drink stays in your cup, walking feels slightly unsteady

ModerateNoticeable bumps — stay seated with seatbelt on, service may pause

HeavyStrong jolts — unsecured items move, crew seated. Rare but possible

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Best time to fly SEA–LHR

Turbulence by month

Smooth

Light

Moderate

Rough

Best seat on SEA–LHR

Boeing 757

Front

Rows 1–13

Light

✓ Wing

Rows 14–24

Smoothest

Rear

Rows 25+

Rougher

Wing seats are over the center of gravity — least affected by turbulence.

What you'll see in the app

Full forecast, live map & seat recommendations

Similar routes

Other popular routes with turbulence data

SEA → LAX

Seattle → Los Angeles

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Is turbulence getting worse?

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Turbulence Forecast Map

Global turbulence outlook

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Passenger Reports

Some light chop crossing the jet stream — seatbelt sign came on for maybe 20 minutes but nothing to worry about. Typical for this route in May.

Regular traveler · May

Flew Seattle–London in June, had some light turbulence in the middle portion of the flight. Brief and nothing concerning. This route is usually fine.

Business traveler · June

The 9h 40m flight had some light shaking around the halfway point. Nothing spilled, nobody panicked. Just normal flying.

Leisure traveler · March

All SEA routes→ All LHR routes→

Frequently asked questions

Is the Seattle to London flight turbulent?

The SEA–LHR route typically experiences light turbulence. The turbulence score for this route is 42.4/100.

When is turbulence worst on SEA to LHR?

Turbulence peaks mid-flight over the Atlantic. First and last hour are usually smooth. Check the turbulence chart above for the typical pattern along this specific route.

Which seat is smoothest on SEA to LHR?

Wing seats are always the smoothest. On a Boeing 757 (the most common aircraft on this route), that's rows 14–24. Avoid the very rear of the aircraft — it amplifies turbulence motion.

How long is the flight from SEA to LHR?

The SEA to LHR flight takes approximately 9h 40m, covering 4,785 miles (4,158 nautical miles).

Which airlines fly SEA to LHR?

The main airlines operating this route are American Airlines, United, Delta, flying Boeing 757 · Airbus A330 aircraft.

Data Sources

PIREP — Pilot reports (PIREPs) submitted via FAA/ICAO systems, aggregated over 12+ months of historical data
SIGMET / AIRMET — Significant Meteorological Information bulletins from NOAA Aviation Weather Center
EDR data — Eddy Dissipation Rate measurements from commercial aircraft (ADS-B derived turbulence intensity)
Seasonal patterns — 5-year rolling averages of turbulence frequency and intensity by month for this route

Scores represent typical conditions. Actual turbulence varies daily. For real-time forecasts, use the Turbulence Forecast app. · About our data