Best Time to Fly IAH to ONT: On-Time Stats by Hour & Airline
George Bush Intercontinental/Houston → Ontario International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 78.2% of Houston (IAH) to Ontario (ONT) flights arrived on time (561 scheduled flights). That is 0.6 points above the national average of 77.6%.
Among 2 airlines, United Airlines led with 78.8% on time and Frontier Airlines was last with 76.9%.
Over 24 months, Tuesday was the most reliable day (77% on time) and June the worst month (56%).
The cancellation rate was 0.2% (US average 1.8%).
IAH 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 |
|---|---|---|---|---|
| United Airlines | 78.8% | 65 min | 0.0% | 365 |
| Frontier Airlines | 76.9% | 54 min | 0.5% | 196 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAH to ONT
On-time arrival % by scheduled departure hour (local time), 1,104 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | Limited data | 12 | |
| 6am–7am | 92.0% | 0.0% | 50 |
| 10am–11am | Limited data | 12 | |
| 11am–12pm | Limited data | 11 | |
| 12pm–1pm | 52.0% | 2.9% | 105 |
| 1pm–2pm | Limited data | 14 | |
| 2pm–3pm | Limited data | 27 | |
| 3pm–4pm | Limited data | 20 | |
| 4pm–5pm | 69.4% | 0.0% | 36 |
| 5pm–6pm | 52.6% | 1.7% | 58 |
| 6pm–7pm | Limited data | 1 | |
| 7pm–8pm | 59.9% | 1.4% | 139 |
| 8pm–9pm | 75.7% | 0.3% | 617 |
| 9pm–10pm | Limited data | 2 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on IAH 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 | 23 | ||
| Christmas & New Year (Dec 20 - Jan 3) | 73.2% | +0.6 pts | 2.3% | 43 |
| Summer peak (Jun 15 - Aug 15) | 64.6% | -7.9 pts | 0.5% | 196 |
| All other days | 72.6% | — | 0.7% | 842 |
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).