How long is flight CX251?

The LHR to HKG route is the basis for the schedule. View the full route forecast and typical duration on the Turbcast route page.

Flight CX251

CX251 Turbulence ForecastCathay Pacific · LHR → HKG

About flight CX251

Airline: Cathay Pacific (CX)
Route: LHR → HKG
Typical Aircraft: A359
Distance: 9,631 km
Duration: 11h 42m
Cruise Altitude: FL410

See today’s turbulence forecast

Cathay Pacific CX251 flies the jet-stream exposed corridor from London to Hong Kong. Conditions change hour to hour - view the live forecast for your departure date.

View live forecast

Check CX251 on a specific date

Turbulence on the LHR → HKG route

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. Flying eastbound, aircraft usually benefit from tailwinds near the jet core, which trims flight time - but the edges of the jet are where clear-air turbulence most often sits.

Calmest season: Late spring to early autumn (May-September). Seasonal turbulence on this route is modest - most variation comes from day-to-day weather rather than strong seasonal cycles.

Full LHR to HKG route guide

Frequently asked questions

Is CX251 usually a bumpy flight?

Cathay Pacific CX251 operates between LHR and HKG. Whether it’s bumpy depends on the day’s weather - Turbcast pulls live NOAA aviation-grade data so you can check the actual forecast for your departure date rather than relying on averages.

What aircraft does CX251 use?

CX251 is typically operated by the A359. Aircraft swaps happen - confirm with your booking before flying.

How long is the LHR to HKG flight?

Approximately 11h 42m direct, covering 9,631 km at a typical cruise of FL410.

When does CX251 have the smoothest weather?

Historically calmest during Late spring to early autumn (May-September). Forecast accuracy improves as you get closer to departure - within 48 hours the NOAA WAFS model is at peak skill.