Ontario International (ONT) Delays and On-Time Departures
Ontario, CA · ranked 153rd of 333 airports for on-time departures
Data through July 2026 · Last updated October 18, 2026
81.0% of the 25,854 flights scheduled to depart Ontario (ONT) in the last 12 months left on time, 3.5 points above the US average of 77.4%.
That ranks 153rd of 333 US airports tracked on this site, with 0.9% of departures cancelled.
Among airlines at Ontario (ONT), Envoy Air left on time most often (93.3%).
Over 24 months, Tuesday was the most reliable day (86% on time) and June the worst month (76%).
Best time of day to fly out of Ontario (ONT)
On-time departure % by scheduled departure hour (local time), last 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 12am–1am | 77.8% | 1.6% | 321 |
| 5am–6am | 95.0% | 0.4% | 3,102 |
| 6am–7am | 93.5% | 0.6% | 7,571 |
| 7am–8am | 93.1% | 1.1% | 2,955 |
| 8am–9am | 90.5% | 0.7% | 2,708 |
| 9am–10am | 90.4% | 0.6% | 2,440 |
| 10am–11am | 84.1% | 0.9% | 3,632 |
| 11am–12pm | 84.9% | 0.8% | 2,985 |
| 12pm–1pm | 79.0% | 1.1% | 3,213 |
| 1pm–2pm | 76.6% | 0.5% | 3,838 |
| 2pm–3pm | 71.5% | 1.3% | 2,366 |
| 3pm–4pm | 72.3% | 0.9% | 2,098 |
| 4pm–5pm | 75.8% | 0.6% | 3,016 |
| 5pm–6pm | 79.5% | 0.7% | 2,500 |
| 6pm–7pm | 72.0% | 0.8% | 2,723 |
| 7pm–8pm | 73.8% | 0.6% | 2,026 |
| 8pm–9pm | 68.2% | 0.7% | 1,538 |
| 9pm–10pm | 67.2% | 0.7% | 907 |
| 10pm–11pm | 84.3% | 1.2% | 1,459 |
| 11pm–12am | 78.8% | 2.8% | 1,032 |
Airlines at ONT ranked by on-time departures
Last 12 months. Airlines with fewer than 30 departures are marked “limited data”.
| Airline | On-time departures | On-time arrivals | Cancelled | Departures |
|---|---|---|---|---|
| Envoy Air | 93.3% | 88.9% | 0.0% | 45 |
| Delta Air Lines | 89.1% | 90.7% | 1.4% | 1,865 |
| SkyWest Airlines | 89.0% | 87.5% | 0.4% | 1,724 |
| Alaska Airlines | 85.6% | 84.8% | 1.4% | 2,067 |
| United Airlines | 83.2% | 79.6% | 0.5% | 2,460 |
| American Airlines | 82.3% | 82.2% | 2.0% | 3,608 |
| Southwest Airlines | 77.8% | 81.3% | 0.4% | 11,662 |
| Frontier Airlines | 76.8% | 75.5% | 1.3% | 2,258 |
| JetBlue | 63.6% | 70.4% | 1.8% | 165 |
80%+ good 70–79.9% fair <70% poor
Best day to fly out of ONT
On-time departures by day, 24 months.
Best month to fly out of ONT
On-time departures by month, 24 months.
Holiday travel at Ontario (ONT)
On-time departures during holiday periods compared with all other days, last 24 months.
| Period | On-time departures | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 83.4% | -0.8 pts | 0.3% | 1,010 |
| Christmas & New Year (Dec 20 - Jan 3) | 76.1% | -8.1 pts | 0.9% | 2,087 |
| Summer peak (Jun 15 - Aug 15) | 78.2% | -6.0 pts | 1.0% | 9,596 |
| All other days | 84.2% | — | 0.8% | 39,737 |
Monthly on-time departure trend at ONT
On-time departure % each month, with the 12-month US average for reference.
Routes from Ontario (ONT)
Every route from ONT with its own page, by number of flights (last 12 months, on-time arrivals).
| To | On time | Cancelled | Flights |
|---|---|---|---|
| ONT → Phoenix (PHX) | 82.5% | 0.6% | 3,027 |
| ONT → Denver (DEN) | 81.0% | 0.3% | 2,643 |
| ONT → Seattle (SEA) | 86.3% | 1.1% | 2,505 |
| ONT → Las Vegas (LAS) | 77.0% | 0.9% | 2,476 |
| ONT → Dallas/Fort Worth (DFW) | 79.3% | 2.7% | 2,297 |
| ONT → Sacramento (SMF) | 85.6% | 0.3% | 2,114 |
| ONT → Oakland (OAK) | 86.5% | 0.4% | 1,471 |
| ONT → San Jose (SJC) | 85.5% | 0.1% | 1,319 |
| ONT → San Francisco (SFO) | 62.2% | 0.8% | 1,309 |
| ONT → Salt Lake City (SLC) | 91.6% | 0.9% | 1,239 |
| ONT → Atlanta (ATL) | 89.3% | 1.8% | 937 |
| ONT → Portland (PDX) | 90.2% | 0.7% | 565 |
| ONT → Houston (IAH) | 85.2% | 1.1% | 561 |
| ONT → Honolulu (HNL) | 86.7% | 0.2% | 423 |
| ONT → Dallas (DAL) | 74.2% | 1.5% | 399 |
| ONT → Houston (HOU) | 65.2% | 0.0% | 362 |
| ONT → Chicago (MDW) | 90.2% | 0.3% | 360 |
| ONT → Austin (AUS) | 74.3% | 0.3% | 337 |
| ONT → Nashville (BNA) | 77.4% | 0.6% | 336 |
| ONT → Charlotte (CLT) | 86.7% | 1.2% | 327 |
| ONT → Chicago (ORD) | 80.6% | 1.4% | 291 |
| ONT → Baltimore (BWI) | 83.9% | 0.4% | 281 |
| ONT → New York (JFK) | 70.4% | 1.8% | 165 |