SFO to ONT flight delays
San Francisco, CA (SFO) Ontario, CA (ONT) · 363 miles
120 flights · March 2025 – August 2026 · US Bureau of Transportation Statistics
71.43%
Arrived on time
Within 15 minutes of schedule
0.83%
Cancelled
Share of scheduled flights
43 min
When late, late by
Average across delayed arrivals
13 min
Delay per flight
Averaged over every flight flown
What the record says about this route
The two directions do not behave alike. ONT to SFO arrives on time 38.1 points less often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
This route does better than its own airport. Departures from SFO overall run 7.5 points less punctual than this particular one — so whatever congestion SFO has, this route is largely escaping it.
Flights from San Francisco to Ontario run late more often than the average route, though not severely.
Every airline on SFO to ONT
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| United Airlines | 60 | 76.67% | 0% | 31 min | — |
| Frontier Airlines | 30 | 62.07% | 3.33% | 67 min | — |
| SkyWest Airlines | 30 | 70% | 0% | 30 min | — |
The return leg
ONT to SFO Ontario back to San Francisco 33.33% on time FOther routes from San Francisco
Common questions
Are flights from San Francisco to Ontario usually delayed?
71.43% of flights on the SFO to ONT route arrived within 15 minutes of schedule, so roughly 3 in every ten arrived late. That is worse than the average route in this record.
How often are SFO to ONT flights cancelled?
0.83% of scheduled flights did not operate — about 8 in every thousand. That is in the normal range.
When SFO to ONT flights are late, how late are they?
About 43 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on SFO to ONT during March 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →