Best Time to Fly BWI to ONT: On-Time Stats by Hour & Airline
Baltimore/Washington International Thurgood Marshall → Ontario International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 63.2% of Baltimore (BWI) to Ontario (ONT) flights arrived on time (281 scheduled flights). That is 14.4 points below the national average of 77.6%.
Southwest Airlines was the only reporting airline with regular flights on this route.
September has been the best month (90% on time) and Saturday the weakest day of the week (48%).
0.4% of flights were cancelled, versus 1.8% nationally.
BWI 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 | 63.2% | 48 min | 0.4% | 281 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly BWI to ONT
On-time arrival % by scheduled departure hour (local time), 338 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 9am–10am | 84.2% | 1.7% | 58 |
| 10am–11am | Limited data | 1 | |
| 11am–12pm | Limited data | 15 | |
| 12pm–1pm | 72.9% | 0.0% | 48 |
| 1pm–2pm | 56.4% | 0.0% | 39 |
| 2pm–3pm | Limited data | 17 | |
| 3pm–4pm | 56.2% | 0.0% | 64 |
| 4pm–5pm | Limited data | 7 | |
| 5pm–6pm | Limited data | 11 | |
| 6pm–7pm | Limited data | 17 | |
| 7pm–8pm | Limited data | 8 | |
| 8pm–9pm | 52.8% | 0.0% | 53 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on BWI 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) | Limited data | 6 | ||
| Christmas & New Year (Dec 20 - Jan 3) | Limited data | 11 | ||
| Summer peak (Jun 15 - Aug 15) | 61.1% | -5.4 pts | 0.9% | 109 |
| All other days | 66.5% | — | 0.0% | 212 |
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).