IAH to ONT flight delays & on-time performance
Nonstop flights from George Bush Intercontinental Airport to Ontario International Airport · 1,334 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at IAH or ONT right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Houston (IAH) to Ontario (ONT) arrived on time 78% of the time in Aug 2025 – Jul 2026, in line with the national average.
- 0.2% were cancelled, and 8% arrived an hour or more late.
- United Airlines was the most punctual airline here (79% on time); Frontier Airlines was the least (77%).
- Departures scheduled around 6am did best (92% on time); around 3pm did worst (65%).
- Tuesday was the most reliable day to fly (85% on time) and Monday the least (73%).
- The largest source of delay minutes was late-arriving aircraft (58%).
Which airline is most on time from IAH to ONT?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| United Airlines | 79% | 0.0% | 15 min | 8.8% | 365 |
| Frontier Airlines | 77% | 0.5% | 13 min | 6.7% | 196 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am92%12 flights
- 6am92%50 flights
- 10am100%12 flights
- 2pm71%24 flights
- 3pm65%17 flights
- 4pm69%35 flights
- 5pm67%37 flights
- 7pm74%74 flights
- 8pm79%293 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday73%1.0% cancelled
- Tuesday85%0.0% cancelled
- Wednesday79%0.0% cancelled
- Thursday78%0.0% cancelled
- Friday76%0.0% cancelled
- Saturday78%0.0% cancelled
- Sunday80%0.0% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft58%
- Airline (crew, maintenance, cleaning, fueling)33%
- Air traffic control & airport congestion7%
- Extreme weather2%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Airline (crew, maintenance, cleaning, fueling)100%
- Extreme weather0%
- Air traffic control & airport congestion0%
- Security0%
IAH to ONT: common questions
- How often are IAH to ONT flights on time?
- 78% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Houston to Ontario cancelled?
- 0.2% of scheduled flights were cancelled (1 of 561).
- How long are typical delays?
- Across all flights the average arrival delay was 14 min (early arrivals count as zero). Flights that were late arrived 61 min behind schedule on average, and 8.1% of flights were an hour or more late.
- How long is taxi time at IAH?
- Flights on this route spent 21 min taxiing from the gate to takeoff on average.
Related routes
Return trip: ONT to IAH — 85% on time
More flights from Houston
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: IAH → ONT, nonstop flights by US airlines that report to the DOT. How we calculate this.