San Francisco (SFO) to Ontario (ONT): On-Time Performance
Data through July 2026
San Francisco (SFO) to Ontario (ONT) effectively runs on two schedules. In April 2025, 92% of arrivals were on time; in November 2025 that fell to 68% — a 24-point seasonal swing. Across the full period the route averages 79% on-time against a national 78%.
- On-time
- 79%
- arrived <15 min late
- Avg delay
- 15 min
- completed flights
- Cancelled
- 1.0%
- Flights/day
- 3.6
- last 12 months
- Duration
- 1h 29m
- scheduled
- Distance
- 363 mi
Best airline from SFO to ONT
3 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 82% | 11 min | 0.4% | 1,582 |
| SkyWest Airlines | 81% | 13 min | 1.6% | 943 |
| Frontier Airlines | 68% | 31 min | 1.8% | 501 |
Monthly on-time trend
Best time to fly from SFO to ONT
Aim for departures around 7 p.m. (92% on-time); avoid 10 p.m. departures (48%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 76% | 21 min |
| Tuesdaybest | 84% | 7 min |
| Wednesday | 83% | 10 min |
| Thursday | 76% | 15 min |
| Friday | 77% | 16 min |
| Saturday | 82% | 12 min |
| Sunday | 79% | 20 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft52%
- Airline operations32%
- National airspace system13%
- Weather4%
Frequently asked questions
- How often are flights from SFO to ONT delayed?
- 21% of SFO–ONT 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 15 minutes.
- Which airline is most reliable from SFO to ONT?
- United Airlines has the best on-time record on this route at 82%, based on 1,582 flights. 3 airlines flew SFO–ONT frequently enough to compare in this period.
- What is the best time of day to fly from SFO to ONT?
- Departures around 7 p.m. have the best record (92% on-time), while departures around 10 p.m. have the worst (48%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SFO to ONT?
- The scheduled SFO–ONT flight time averages 1h 29m over 363 miles. Actual arrival times vary — flights on this route land 15+ minutes late 21% of the time.
- How often are SFO to ONT flights cancelled?
- 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 SFO to ONT?
- November 2025 was the roughest month in this dataset, with only 68% of arrivals on time. The best was April 2025 at 92%. If your dates are flexible, that 24-point gap is worth planning around.
Explore related pages
More routes from SFO
Other ways to fly to Ontario (ONT)
Related guides
Based on 3,026 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.