85% of flights from Ontario to Houston arrived on time over the past 12 months. That is better than the typical U.S. route. Most reliable airline: United Airlines (91%). 6% 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 ONT → IAH: when a flight was late, it was under 45 minutes late 58% of the time. About 1 in 23 flights landed an hour or more late, and 1 in 96 three hours or more; 1.2% were cancelled outright.
- On time or early85%
- 15–30 min late6.1%
- 30–60 min late3.0%
- 1–2 hours late2.1%
- 2–3 hours late1.2%
- 3+ hours late1.0%
- Diverted0.0%
- Cancelled1.2%
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 | 91% | 0.6% | −6 min | 2.8% | +95 min | United Airlines |
| Frontier Airlines | 218 | 76% | 2.3% | −7 min | 6.9% | +62 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 ONT). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | United Airlines |
|---|---|
| 6 a.m. | 91% |
By month
Each calendar month pooled over 2023–2026. Best: August (83%). Worst: June (71%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 99 | — | — |
| Tuesday | 70 | — | — |
| Wednesday | 69 | — | — |
| Thursday | 80 | — | — |
| Friday | 102 | 81% | 2.9% |
| Saturday | 66 | — | — |
| Sunday | 88 | — | — |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: airline 5 · weather 2
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 |
|---|---|---|---|---|---|---|
| UA 1936 | 6:00 a.m. | 353 | 91% | 0.6% | −6 min | United Airlines |
| F9 3132 | 5:43 p.m. | 129 | 74% | 2.3% | −8 min | Frontier Airlines |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Ontario or Houston. None has been clearly more reliable than ONT → IAH.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| ONT → IAH (this route) | 574 | 85% | 1.2% |
| SNA → IAH Orange County John Wayne to Houston Bush Intercontinental | 1,092 | 88% | 0.0% |
| LAX → IAH Los Angeles LAX to Houston Bush Intercontinental | 5,143 | 84% | 0.5% |
| LGB → HOU Long Beach to Houston Hobby | 440 | 77% | 0.2% |
| LAX → HOU Los Angeles LAX to Houston Hobby | 1,194 | 69% | 0.2% |
Questions
How often are flights from ONT to IAH on time?
85% of 574 scheduled flights from Ontario, CA to Houston, TX arrived within 15 minutes of schedule between September 2025 and August 2026. 1.2% were cancelled.
Which airline is most on time from ONT to IAH?
United Airlines: 91% of its 356 flights on the route arrived on time. Frontier Airlines: 76%.
What month has the most delays from ONT to IAH?
June (71% on time). The best month is August (83%), over 2023–2026.
Related
- IAH → ONT (return)
- Ontario (ONT) delays by hour
- Flights into Houston Bush Intercontinental (IAH)
- 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.