How long is flight UA1?

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

Flight UA1

UA1 Turbulence ForecastUnited Airlines · SFO → SIN

About flight UA1

San Francisco to Singapore - one of the longest scheduled flights operated by a US carrier.

Airline: United Airlines (UA)
Route: SFO → SIN
Typical Aircraft: B789
Distance: 13,582 km
Duration: 16h 18m
Cruise Altitude: FL410

See today’s turbulence forecast

United Airlines UA1 flies the jet-stream + mountain-wave corridor from San Francisco to Singapore. Conditions change hour to hour - view the live forecast for your departure date.

View live forecast

Check UA1 on a specific date

Turbulence on the SFO → SIN 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. The route crosses or passes near the Rocky Mountains, 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.

Calmest season: Late spring to early autumn (May-September). 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.

Full SFO to SIN route guide

Frequently asked questions

Is UA1 usually a bumpy flight?

United Airlines UA1 operates between SFO and SIN. 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 UA1 use?

UA1 is typically operated by the B789. Aircraft swaps happen - confirm with your booking before flying.

How long is the SFO to SIN flight?

Approximately 16h 18m direct, covering 13,582 km at a typical cruise of FL410.

When does UA1 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.