Ontario (ONT) to Houston (IAH): On-Time Performance
Data through July 2026
Ontario (ONT) to Houston (IAH) effectively runs on two schedules. In February 2026, 100% of arrivals were on time; in July 2024 that fell to 60% — a 40-point seasonal swing. Across the full period the route averages 83% on-time against a national 78%.
- On-time
- 83%
- arrived <15 min late
- Avg delay
- 14 min
- completed flights
- Cancelled
- 1.4%
- Flights/day
- 1.5
- last 12 months
- Duration
- 3h 12m
- scheduled
- Distance
- 1,334 mi
Best airline from ONT to IAH
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 89% | 9 min | 0.9% | 761 |
| Frontier Airlines | 70% | 22 min | 2.3% | 390 |
Monthly on-time trend
Best time to fly from ONT to IAH
Aim for departures around 5 a.m. (90% on-time); avoid 2 p.m. departures (57%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 75% | 24 min |
| Tuesdaybest | 91% | 8 min |
| Wednesday | 79% | 15 min |
| Thursday | 87% | 11 min |
| Friday | 79% | 15 min |
| Saturday | 90% | 7 min |
| Sunday | 84% | 11 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft40%
- Airline operations33%
- National airspace system27%
- Weather1%
Frequently asked questions
- How often are flights from ONT to IAH delayed?
- 17% of ONT–IAH 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 14 minutes.
- Which airline is most reliable from ONT to IAH?
- United Airlines has the best on-time record on this route at 89%, based on 761 flights. 2 airlines flew ONT–IAH frequently enough to compare in this period.
- What is the best time of day to fly from ONT to IAH?
- Departures around 5 a.m. have the best record (90% on-time), while departures around 2 p.m. have the worst (57%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from ONT to IAH?
- The scheduled ONT–IAH flight time averages 3h 12m over 1,334 miles. Actual arrival times vary — flights on this route land 15+ minutes late 17% of the time.
- How often are ONT to IAH flights cancelled?
- 1.4% 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 ONT to IAH?
- July 2024 was the roughest month in this dataset, with only 60% of arrivals on time. The best was February 2026 at 100%. If your dates are flexible, that 40-point gap is worth planning around.
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Based on 1,151 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.