86% of flights from Ontario to San Jose arrived on time over the past 12 months. That is better than the typical U.S. route. The 6 a.m. departures ran on time 97% of the time; the 7 p.m. ones 65%. 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 ONT → SJC: when a flight was late, it was under 45 minutes late 59% of the time. About 1 in 23 flights landed an hour or more late, and 1 in 189 three hours or more; 0.1% were cancelled outright.
- On time or early86%
- 15–30 min late5.2%
- 30–60 min late4.5%
- 1–2 hours late3.0%
- 2–3 hours late0.8%
- 3+ hours late0.5%
- Diverted0.0%
- Cancelled0.1%
Share of all 1,320 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 | 1,320 | 86% | 0.1% | −10 min | 4.3% | +57 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 ONT). Delays build through the day as late planes knock on, so early flights usually do best.
Last flight of the day
On ONT → SJC, each airline's last flight of the day was cancelled 0.0% of the time, against 0.1% for its earlier flights, so here the last flight is actually the safer one. It arrived 3+ hours late 0.8% of the time (earlier flights: 0.4%). 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 | 6:45 p.m. | 0.0% | 0.8% | 0.1% | 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: January (91%). Worst: July (81%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 210 | 87% | 0.0% |
| Tuesday | 175 | 91% | 0.6% |
| Wednesday | 172 | 89% | 0.0% |
| Thursday | 202 | 86% | 0.0% |
| Friday | 204 | 84% | 0.0% |
| Saturday | 155 | 85% | 0.0% |
| Sunday | 202 | 79% | 0.0% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: airline 1
Month by month
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Jun 13, 2026 | 3 | 0% | 0 |
| Oct 13, 2025 | 4 | 25% | 0 |
| Jun 14, 2026 | 4 | 25% | 0 |
| Nov 8, 2025 | 3 | 33% | 0 |
| Dec 27, 2025 | 3 | 33% | 0 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Ontario or San Jose. None has been clearly more reliable than ONT → SJC.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| ONT → SJC (this route) | 1,320 | 86% | 0.1% |
| LAX → MRY Los Angeles LAX to Monterey | 842 | 88% | 0.6% |
| LGB → OAK Long Beach to Oakland | 1,568 | 88% | 0.4% |
| LGB → SJC Long Beach to San Jose | 1,251 | 86% | 0.2% |
| ONT → OAK Ontario to Oakland | 1,450 | 86% | 0.5% |
| SNA → SJC Orange County John Wayne to San Jose | 2,677 | 85% | 0.8% |
| BUR → SJC Hollywood Burbank to San Jose | 2,133 | 85% | 1.2% |
Questions
How often are flights from ONT to SJC on time?
86% of 1,320 scheduled flights from Ontario, CA to San Jose, 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 ONT to SJC?
Flights scheduled to leave at 6 a.m. were the most reliable (97% on time). The 7 p.m. departures were the least (65%).
What month has the most delays from ONT to SJC?
July (81% on time). The best month is January (91%), over 2023–2026.
Is the last flight of the day from ONT to SJC more likely to be cancelled?
No, the opposite. Each airline's last ONT–SJC flight of the day was cancelled 0.0% of the time over the past year, against 0.1% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- SJC → ONT (return)
- Ontario (ONT) delays by hour
- Flights into San Jose (SJC)
- 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.