Best Time to Fly OAK to ONT: On-Time Stats by Hour & Airline
Oakland International → Ontario International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 81.8% of Oakland (OAK) to Ontario (ONT) flights arrived on time (1,471 scheduled flights). That is 4.1 points above the national average of 77.6%.
Southwest Airlines was the only reporting airline with regular flights on this route.
January has been the best month (93% on time) and Thursday the weakest day of the week (81%).
0.4% of flights were cancelled, versus 1.8% nationally.
OAK to ONT on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlines | 81.8% | 47 min | 0.4% | 1,471 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly OAK to ONT
On-time arrival % by scheduled departure hour (local time), 3,050 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 100.0% | 0.0% | 37 |
| 6am–7am | 97.4% | 0.6% | 540 |
| 7am–8am | 98.7% | 1.2% | 80 |
| 8am–9am | 97.8% | 0.0% | 92 |
| 9am–10am | 93.3% | 1.0% | 196 |
| 10am–11am | 91.0% | 0.0% | 212 |
| 11am–12pm | 87.8% | 0.0% | 180 |
| 12pm–1pm | 82.7% | 0.5% | 186 |
| 1pm–2pm | 85.9% | 0.6% | 171 |
| 2pm–3pm | 86.9% | 1.6% | 62 |
| 3pm–4pm | 81.5% | 0.0% | 178 |
| 4pm–5pm | 78.1% | 0.0% | 155 |
| 5pm–6pm | 73.4% | 1.0% | 194 |
| 6pm–7pm | 88.6% | 0.4% | 273 |
| 7pm–8pm | 61.8% | 0.0% | 102 |
| 8pm–9pm | 68.2% | 0.0% | 324 |
| 9pm–10pm | 73.3% | 0.0% | 60 |
| 10pm–11pm | Limited data | 8 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on OAK to ONT
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 82.8% | -3.9 pts | 0.0% | 58 |
| Christmas & New Year (Dec 20 - Jan 3) | 72.6% | -14.1 pts | 0.0% | 113 |
| Summer peak (Jun 15 - Aug 15) | 81.8% | -4.9 pts | 0.0% | 516 |
| All other days | 86.7% | — | 0.5% | 2,363 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).