About 1 in 3 AS 489 flights from Seattle arrived 15+ minutes late, diverted or cancelled over the past year (31%); 0.4% were cancelled. The typical flight landed 2 minutes late.
AS 489: SEA → ONT
Scheduled to leave Seattle at 8:33 p.m. local time. Over the past year it arrived on time 69% of the time (224 flights), in line with other AS flights on the route at that hour (70%). Last seen in the data Aug 31, 2026.
Usually Alaska Airlines's last flight of the day from Seattle to Ontario (99% of days). Alaska Airlines's last SEA–ONT flight was cancelled 0.5% of the time, against 1.9% for its earlier ones. If it's cancelled, the next Alaska Airlines flight is usually around 8:33 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 39 | 72% |
| Tuesday | 26 | 69% |
| Wednesday | 26 | 65% |
| Thursday | 37 | 73% |
| Friday | 37 | 59% |
| Saturday | 21 | 76% |
| Sunday | 38 | 71% |
Why it was late
All flights SEA → ONT · Connecting off AS 489? Check the risk
Questions
How often is AS 489 from SEA to ONT late?
Alaska Airlines 489 from Seattle, WA to Ontario, CA arrived 15 or more minutes late, was diverted or was cancelled on 31% of 224 scheduled flights between September 2025 and August 2026. 0.4% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Alaska Airlines for today's flight. Method.