Houston (IAH) to Ontario (ONT): On-Time Performance
Data through July 2026
Houston (IAH) to Ontario (ONT) effectively runs on two schedules. In February 2026, 92% of arrivals were on time; in June 2025 that fell to 34% — a 58-point seasonal swing. Across the full period the route averages 70% on-time against a national 78%.
- On-time
- 70%
- arrived <15 min late
- Avg delay
- 20 min
- completed flights
- Cancelled
- 1.1%
- Flights/day
- 1.5
- last 12 months
- Duration
- 3h 30m
- scheduled
- Distance
- 1,334 mi
Best airline from IAH to ONT
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 73% | 19 min | 0.5% | 762 |
| Frontier Airlines | 64% | 23 min | 2.3% | 391 |
Monthly on-time trend
Best time to fly from IAH to ONT
Aim for departures around 6 a.m. (92% on-time); avoid 12 p.m. departures (52%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 63% | 23 min |
| Tuesdaybest | 77% | 21 min |
| Wednesday | 69% | 17 min |
| Thursday | 70% | 19 min |
| Friday | 72% | 22 min |
| Saturday | 73% | 18 min |
| Sunday | 67% | 22 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft50%
- Airline operations36%
- National airspace system11%
- Weather3%
Frequently asked questions
- How often are flights from IAH to ONT delayed?
- 30% of IAH–ONT flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 20 minutes.
- Which airline is most reliable from IAH to ONT?
- United Airlines has the best on-time record on this route at 73%, based on 762 flights. 2 airlines flew IAH–ONT frequently enough to compare in this period.
- What is the best time of day to fly from IAH to ONT?
- Departures around 6 a.m. have the best record (92% on-time), while departures around 12 p.m. have the worst (52%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from IAH to ONT?
- The scheduled IAH–ONT flight time averages 3h 30m over 1,334 miles. Actual arrival times vary — flights on this route land 15+ minutes late 30% of the time.
- How often are IAH to ONT flights cancelled?
- 1.1% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from IAH to ONT?
- June 2025 was the roughest month in this dataset, with only 34% of arrivals on time. The best was February 2026 at 92%. If your dates are flexible, that 58-point gap is worth planning around.
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Based on 1,153 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.