ONT to SJC flight delays & on-time performance
Nonstop flights from Ontario International Airport to Mineta San Jose International Airport · 333 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at ONT or SJC right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Ontario (ONT) to San Jose (SJC) arrived on time 86% of the time in Aug 2025 – Jul 2026, better than the 78% national average.
- 0.1% were cancelled, and 4% arrived an hour or more late.
- Southwest Airlines is the only airline reporting nonstop flights on this route.
- Departures scheduled around 8am did best (100% on time); around 7pm did worst (66%).
- Tuesday was the most reliable day to fly (92% on time) and Sunday the least (79%).
- The largest source of delay minutes was late-arriving aircraft (78%).
Which airline is most on time from ONT to SJC?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Southwest Airlines | 86% | 0.1% | 9 min | 4.2% | 1,319 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am100%26 flights
- 6am97%218 flights
- 7am97%31 flights
- 8am100%51 flights
- 9am92%51 flights
- 10am94%130 flights
- 11am97%60 flights
- 12pm90%98 flights
- 1pm83%24 flights
- 2pm83%29 flights
- 3pm84%82 flights
- 4pm74%125 flights
- 5pm76%92 flights
- 6pm83%111 flights
- 7pm66%119 flights
- 8pm77%56 flights
- 9pm38%16 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday85%0.0% cancelled
- Tuesday92%0.6% cancelled
- Wednesday90%0.0% cancelled
- Thursday86%0.0% cancelled
- Friday83%0.0% cancelled
- Saturday86%0.0% cancelled
- Sunday79%0.0% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft78%
- Airline (crew, maintenance, cleaning, fueling)20%
- Air traffic control & airport congestion2%
- Security0%
- Extreme weather0%
Why flights are cancelled
Share of cancellations by reason.
- Airline (crew, maintenance, cleaning, fueling)100%
- Extreme weather0%
- Air traffic control & airport congestion0%
- Security0%
ONT to SJC: common questions
- How often are ONT to SJC flights on time?
- 86% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Ontario to San Jose cancelled?
- 0.1% of scheduled flights were cancelled (1 of 1,319).
- How long are typical delays?
- Across all flights the average arrival delay was 9 min (early arrivals count as zero). Flights that were late arrived 56 min behind schedule on average, and 4.2% of flights were an hour or more late.
- How long is taxi time at ONT?
- Flights on this route spent 10 min taxiing from the gate to takeoff on average.
Related routes
Return trip: SJC to ONT — 82% on time
More flights from Ontario
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: ONT → SJC, nonstop flights by US airlines that report to the DOT. How we calculate this.