SJC to ONT flight delays & on-time performance
Nonstop flights from Mineta San Jose International Airport to Ontario International Airport · 333 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at SJC or ONT right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from San Jose (SJC) to Ontario (ONT) arrived on time 82% of the time in Aug 2025 – Jul 2026, better than the 78% national average.
- 0.2% were cancelled, and 3% arrived an hour or more late.
- Southwest Airlines is the only airline reporting nonstop flights on this route.
- Departures scheduled around 6am did best (98% on time); around 9pm did worst (40%).
- Tuesday was the most reliable day to fly (88% on time) and Sunday the least (74%).
- The largest source of delay minutes was late-arriving aircraft (72%).
Which airline is most on time from SJC to ONT?
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 | 82% | 0.2% | 9 min | 3.3% | 1,317 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 6am98%144 flights
- 7am98%138 flights
- 8am98%81 flights
- 9am96%25 flights
- 10am89%117 flights
- 11am86%150 flights
- 12pm94%33 flights
- 1pm86%36 flights
- 2pm88%32 flights
- 3pm78%51 flights
- 4pm69%98 flights
- 5pm66%71 flights
- 6pm73%82 flights
- 7pm84%82 flights
- 8pm64%120 flights
- 9pm40%56 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday82%0.5% cancelled
- Tuesday88%0.0% cancelled
- Wednesday87%0.0% cancelled
- Thursday84%0.5% cancelled
- Friday79%0.0% cancelled
- Saturday86%0.0% cancelled
- Sunday74%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 aircraft72%
- Airline (crew, maintenance, cleaning, fueling)24%
- Air traffic control & airport congestion3%
- Extreme weather0%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Airline (crew, maintenance, cleaning, fueling)100%
- Extreme weather0%
- Air traffic control & airport congestion0%
- Security0%
SJC to ONT: common questions
- How often are SJC to ONT flights on time?
- 82% 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 San Jose to Ontario cancelled?
- 0.2% of scheduled flights were cancelled (2 of 1,317).
- 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 45 min behind schedule on average, and 3.3% of flights were an hour or more late.
- How long is taxi time at SJC?
- Flights on this route spent 11 min taxiing from the gate to takeoff on average.
Related routes
Return trip: ONT to SJC — 86% on time
More flights from San Jose
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: SJC → ONT, nonstop flights by US airlines that report to the DOT. How we calculate this.