82% of flights from San Jose to Ontario arrived on time over the past 12 months. That is better than the typical U.S. route. The 7 a.m. departures ran on time 98% of the time; the 8 p.m. ones 62%. 4% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for SJC → ONT: when a flight was late, it was under 45 minutes late 66% of the time. About 1 in 30 flights landed an hour or more late, and 1 in 330 three hours or more; 0.2% were cancelled outright.
- On time or early82%
- 15–30 min late8.3%
- 30–60 min late5.9%
- 1–2 hours late2.4%
- 2–3 hours late0.6%
- 3+ hours late0.3%
- Diverted0.1%
- Cancelled0.2%
Share of all 1,318 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| Southwest Airlines | 1,318 | 82% | 0.1% | −8 min | 3.3% | +46 min | Southwest Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at SJC). Delays build through the day as late planes knock on, so early flights usually do best.
Last flight of the day
On SJC → ONT, each airline's last flight of the day was cancelled 0.0% of the time, against 0.2% for its earlier flights, so here the last flight is actually the safer one. It arrived 3+ hours late 0.3% of the time (earlier flights: 0.3%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| Southwest Airlines | 8:15 p.m. | 0.0% | 0.3% | 0.2% | first flight 6:30 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
By month
Each calendar month pooled over 2023–2026. Best: November (91%). Worst: June (77%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 210 | 81% | 0.5% |
| Tuesday | 174 | 89% | 0.0% |
| Wednesday | 171 | 87% | 0.0% |
| Thursday | 202 | 82% | 0.5% |
| Friday | 204 | 79% | 0.0% |
| Saturday | 155 | 85% | 0.0% |
| Sunday | 202 | 74% | 0.0% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: airline 2
Month by month
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Oct 23, 2025 | 4 | 0% | 0 |
| May 24, 2026 | 3 | 0% | 0 |
| Feb 12, 2026 | 4 | 25% | 0 |
| Oct 26, 2025 | 4 | 25% | 0 |
| Jul 13, 2026 | 4 | 25% | 0 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of San Jose or Ontario. MRY → LAX has been 4 points more reliable.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| SJC → ONT (this route) | 1,318 | 82% | 0.1% |
| MRY → LAX Monterey to Los Angeles LAX | 839 | 86% | 0.6% |
| SJC → SNA San Jose to Orange County John Wayne | 2,741 | 85% | 0.8% |
| OAK → LGB Oakland to Long Beach | 1,568 | 85% | 0.3% |
| SJC → LGB San Jose to Long Beach | 1,251 | 84% | 0.2% |
| SJC → LAX San Jose to Los Angeles LAX | 4,669 | 84% | 0.9% |
| OAK → SNA Oakland to Orange County John Wayne | 2,356 | 84% | 0.9% |
Questions
How often are flights from SJC to ONT on time?
82% of 1,318 scheduled flights from San Jose, CA to Ontario, CA arrived within 15 minutes of schedule between September 2025 and August 2026. 0.1% were cancelled.
What is the best time of day to fly SJC to ONT?
Flights scheduled to leave at 7 a.m. were the most reliable (98% on time). The 8 p.m. departures were the least (62%).
What month has the most delays from SJC to ONT?
June (77% on time). The best month is November (91%), over 2023–2026.
Is the last flight of the day from SJC to ONT more likely to be cancelled?
No, the opposite. Each airline's last SJC–ONT flight of the day was cancelled 0.0% of the time over the past year, against 0.2% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- ONT → SJC (return)
- San Jose (SJC) delays by hour
- Flights into Ontario (ONT)
- Southwest Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.