San Jose (SJC) to Ontario (ONT): On-Time Performance
Data through May 2026
San Jose (SJC) to Ontario (ONT) effectively runs on two schedules. In November 2024, 94% of arrivals were on time; in October 2025 that fell to 72% — a 22-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 (95% vs 74%), which matters most in the rough months.
- On-time
- 86%
- arrived <15 min late
- Avg delay
- 8 min
- completed flights
- Cancelled
- 0.2%
- Flights/day
- 3.6
- last 12 months
- Duration
- 1h 17m
- scheduled
- Distance
- 333 mi
Monthly on-time trend
Best time to fly from SJC to ONT
Aim for departures around 6 a.m. (99% on-time); avoid 9 p.m. departures (52%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 87% | 8 min |
| Tuesday | 90% | 6 min |
| Wednesdaybest | 92% | 4 min |
| Thursday | 84% | 9 min |
| Friday | 84% | 8 min |
| Saturday | 90% | 6 min |
| Sunday | 79% | 11 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft70%
- Airline operations26%
- National airspace system3%
Frequently asked questions
- How often are flights from SJC to ONT delayed?
- 14% of SJC–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 SJC to ONT?
- Departures around 6 a.m. have the best record (99% on-time), while departures around 9 p.m. have the worst (52%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SJC to ONT?
- The scheduled SJC–ONT flight time averages 1h 17m over 333 miles. Actual arrival times vary — flights on this route land 15+ minutes late 14% of the time.
- How often are SJC to ONT flights cancelled?
- 0.2% 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 SJC to ONT?
- October 2025 was the roughest month in this dataset, with only 72% of arrivals on time. The best was November 2024 at 94%. If your dates are flexible, that 22-point gap is worth planning around.
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Based on 2,692 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.