81% of flights from Houston to Ontario arrived on time over the past 12 months. That is about the typical U.S. route. Most reliable airline: Frontier Airlines (82%). 7% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for IAH → ONT: when a flight was late, it was under 45 minutes late 55% of the time. About 1 in 14 flights landed an hour or more late, and 1 in 96 three hours or more; 0.2% were cancelled outright.
- On time or early81%
- 15–30 min late6.4%
- 30–60 min late5.6%
- 1–2 hours late5.1%
- 2–3 hours late0.9%
- 3+ hours late1.0%
- Diverted0.2%
- Cancelled0.2%
Share of all 574 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| United Airlines | 356 | 80% | 0.0% | −7 min | 7.9% | +62 min | United Airlines |
| Frontier Airlines | 218 | 82% | 0.5% | −14 min | 5.5% | +58 min | Frontier Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at IAH). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | United Airlines |
|---|---|
| 8 p.m. | 80% |
By month
Each calendar month pooled over 2023–2026. Best: August (73%). Worst: June (54%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 99 | — | — |
| Tuesday | 67 | — | — |
| Wednesday | 69 | — | — |
| Thursday | 83 | — | — |
| Friday | 99 | — | — |
| Saturday | 69 | — | — |
| Sunday | 88 | — | — |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: airline 1
Month by month
Not enough months with data to draw a trend.
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| F9 3131 | 6:10 a.m. | 218 | 82% | 0.5% | −14 min | Frontier Airlines |
| UA 1563 | 8:31 p.m. | 325 | 79% | 0.0% | −8 min | United Airlines |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Houston or Ontario. IAH → SNA has been 7 points more reliable.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| IAH → ONT (this route) | 574 | 81% | 0.2% |
| IAH → SNA Houston Bush Intercontinental to Orange County John Wayne | 1,092 | 88% | 0.0% |
| HOU → LGB Houston Hobby to Long Beach | 440 | 87% | 0.4% |
| IAH → LAX Houston Bush Intercontinental to Los Angeles LAX | 5,147 | 84% | 0.4% |
| HOU → LAX Houston Hobby to Los Angeles LAX | 1,188 | 73% | 0.2% |
Questions
How often are flights from IAH to ONT on time?
81% of 574 scheduled flights from Houston, TX to Ontario, CA arrived within 15 minutes of schedule between September 2025 and August 2026. 0.2% were cancelled.
Which airline is most on time from IAH to ONT?
Frontier Airlines: 82% of its 218 flights on the route arrived on time. United Airlines: 80%.
What month has the most delays from IAH to ONT?
June (54% on time). The best month is August (73%), over 2023–2026.
Related
- ONT → IAH (return)
- Houston Bush Intercontinental (IAH) delays by hour
- Flights into Ontario (ONT)
- United Airlines on-time record
- Frontier Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.