UA2478United Airlines · SEA → ONT
live · 30m ago
Route confirmed United Airlines

UA2478 SeattleSEA · 15:30 OntarioONT · 17:40

UA2478 by United Airlines flies from Seattle (SEA) to Ontario (ONT) for the Mon, Sep 14 departure.

Same number through SEA → SFO → ONT

Right nowOn time · gate B15 · as of 04:38
15:30

departs SEA · on schedule

The route today

live boards
SEASeattleModerate riskSEA delay board →
ONTOntarioHigh riskONT delay board →
SEA→ONTevery carrier, schedules and on-time historyRoute intelligence →

Weather lens

Delay & cancellation outlook for this flight

Measured, 90-day sample
50%Chance of 15+ min delay
1.7%Chance of cancellation
+22 minAvg hub delay right now

Conditions at SEA and ONT are near their clear-air norm right now, so this reflects the route's recent baseline rather than a weather penalty. For this route and airline, under conditions like today's, over the last 90 days.

Pro Flight Search tracking, 90 days · the weather × delay correlation study → · live weather risk by airport →

When it flies

scheduled departures
061422
M
T
W
T
F
S
S

Each mark is a scheduled departure at its origin-local time. Today is highlighted.

Other Seattle to Ontario flights today

same route · United Airlines
UA499departs 07:00
UA2831departs 09:00
UA2281departs 13:16
UA737departs 17:20
UA656departs 19:35

If UA2478 is cancelled, these are the other United Airlines nonstop flights from Seattle to Ontario on the same day, with scheduled departure times in SEA local time. Most flights posting a delay still operate — rebooking usually only beats a very large posted delay. Every airline on this route →

How UA2478 actually runs

Pro Flight Search has tracked every published board update for UA2478 across the SEA and ONT boards: schedule changes, gate pushes and actual clocks. Early read — pattern not clear yet. Only 1 completed leg so far: landed +10 min. Not enough to call it.

The verdict above is that record speaking, so it reflects how UA2478 operates rather than what the timetable promises. Numbers refresh as new flights operate.

Technical record

How this operation is measured

board clocks

Board log

scheduled → actual, per operation
09-13SEA 15:25ONT
09-12SEA 15:30ONT

Board clocks recorded as SEA and ONT published them.

Planning around UA2478? Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure

Cite this data

Journalists, bloggers, and researchers may cite this page with attribution and a link to Pro Flight Search.

Suggested citation

Pro Flight Search — UA2478 Seattle to Ontario on-time performance, measured from the SEA and ONT airport boards.

Canonical URL
https://proflightsearch.com/flight/UA2478
How we measure this →