Oakland (OAK) to Ontario (ONT): On-Time Performance
Data through May 2026
Oakland (OAK) to Ontario (ONT) effectively runs on two schedules. In January 2026, 94% of arrivals were on time; in May 2026 that fell to 74% — a 20-point seasonal swing. Across the full period the route averages 86% on-time against a national 78%. Morning departures also hold up better than evening ones (94% vs 76%), which matters most in the rough months.
- On-time
- 86%
- arrived <15 min late
- Avg delay
- 8 min
- completed flights
- Cancelled
- 0.5%
- Flights/day
- 4.1
- last 12 months
- Duration
- 1h 22m
- scheduled
- Distance
- 362 mi
Monthly on-time trend
Best time to fly from OAK to ONT
Aim for departures around 5 a.m. (100% on-time); avoid 7 p.m. departures (62%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 85% | 7 min |
| Tuesday | 91% | 5 min |
| Wednesdaybest | 91% | 5 min |
| Thursday | 81% | 10 min |
| Friday | 82% | 12 min |
| Saturday | 89% | 5 min |
| Sunday | 84% | 10 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft55%
- Airline operations41%
- National airspace system4%
Frequently asked questions
- How often are flights from OAK to ONT delayed?
- 14% of OAK–ONT flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 8 minutes.
- What is the best time of day to fly from OAK to ONT?
- Departures around 5 a.m. have the best record (100% on-time), while departures around 7 p.m. have the worst (62%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from OAK to ONT?
- The scheduled OAK–ONT flight time averages 1h 22m over 362 miles. Actual arrival times vary — flights on this route land 15+ minutes late 14% of the time.
- How often are OAK to ONT flights cancelled?
- 0.5% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from OAK to ONT?
- May 2026 was the roughest month in this dataset, with only 74% of arrivals on time. The best was January 2026 at 94%. If your dates are flexible, that 20-point gap is worth planning around.
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Based on 3,086 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.