Ontario (ONT) to San Jose (SJC): On-Time Performance
Data through July 2026
The calendar drives reliability on ONT–SJC. October 2024 flights landed on schedule 97% of the time, but June 2026 dropped to 75% — a gap of 21 points. Across the full period the route averages 87% on-time against a national 78%. Morning departures also hold up better than evening ones (96% vs 76%), which matters most in the rough months.
- On-time
- 87%
- arrived <15 min late
- Avg delay
- 8 min
- completed flights
- Cancelled
- 0.1%
- Flights/day
- 3.6
- last 12 months
- Duration
- 1h 15m
- scheduled
- Distance
- 333 mi
Monthly on-time trend
Best time to fly from ONT to SJC
Aim for departures around 8 a.m. (100% on-time); avoid 9 p.m. departures (50%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 86% | 10 min |
| Tuesdaybest | 92% | 5 min |
| Wednesday | 90% | 7 min |
| Thursday | 87% | 8 min |
| Friday | 86% | 9 min |
| Saturday | 87% | 9 min |
| Sunday | 81% | 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 aircraft84%
- Airline operations15%
- National airspace system2%
Frequently asked questions
- How often are flights from ONT to SJC delayed?
- 13% of ONT–SJC flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 8 minutes.
- What is the best time of day to fly from ONT to SJC?
- Departures around 8 a.m. have the best record (100% on-time), while departures around 9 p.m. have the worst (50%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from ONT to SJC?
- The scheduled ONT–SJC flight time averages 1h 15m over 333 miles. Actual arrival times vary — flights on this route land 15+ minutes late 13% of the time.
- How often are ONT to SJC flights cancelled?
- 0.1% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from ONT to SJC?
- June 2026 was the roughest month in this dataset, with only 75% of arrivals on time. The best was October 2024 at 97%. If your dates are flexible, that 21-point gap is worth planning around.
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Based on 2,819 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.