Best Time to Fly ORD to IAH: On-Time Stats by Hour & Airline
Chicago O'Hare International → George Bush Intercontinental/Houston
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 76.1% of Chicago (ORD) to Houston (IAH) flights arrived on time (6,114 scheduled flights). That is 1.5 points below the national average of 77.6%.
United Airlines was the most punctual of the 6 airlines on the route at 80.1%, while American Airlines trailed at 59.3%.
September has been the best month (85% on time) and Friday the weakest day of the week (72%).
1.5% of flights were cancelled, versus 1.8% nationally.
ORD to IAH on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| United Airlines | 80.1% | 68 min | 0.7% | 4,040 |
| Frontier Airlines | 77.8% | 102 min | 3.8% | 263 |
| Republic Airways | 76.8% | 70 min | 2.7% | 367 |
| Envoy Air | 74.6% | 63 min | 1.4% | 353 |
| Spirit Airlines | 65.7% | 94 min | 4.4% | 274 |
| American Airlines | 59.3% | 82 min | 3.1% | 811 |
| PSA Airlines | Limited data | 4 | ||
| SkyWest Airlines | Limited data | 2 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly ORD to IAH
On-time arrival % by scheduled departure hour (local time), 11,763 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 12am–1am | Limited data | 1 | |
| 5am–6am | 91.0% | 0.8% | 527 |
| 6am–7am | 88.8% | 1.2% | 671 |
| 7am–8am | 85.5% | 0.8% | 1,003 |
| 8am–9am | 85.1% | 1.1% | 717 |
| 9am–10am | 77.5% | 1.1% | 765 |
| 10am–11am | 84.3% | 0.2% | 871 |
| 11am–12pm | 92.0% | 0.0% | 50 |
| 12pm–1pm | 83.7% | 0.4% | 780 |
| 1pm–2pm | 73.7% | 1.4% | 517 |
| 2pm–3pm | 72.2% | 0.4% | 1,001 |
| 3pm–4pm | 68.2% | 1.5% | 648 |
| 4pm–5pm | 70.1% | 0.5% | 640 |
| 5pm–6pm | 75.9% | 2.6% | 578 |
| 6pm–7pm | 70.8% | 1.2% | 603 |
| 7pm–8pm | 64.4% | 1.2% | 412 |
| 8pm–9pm | 63.9% | 2.4% | 1,026 |
| 9pm–10pm | 68.1% | 2.4% | 931 |
| 10pm–11pm | Limited data | 16 | |
| 11pm–12am | Limited data | 6 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on ORD to IAH
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 68.6% | -9.7 pts | 4.2% | 216 |
| Christmas & New Year (Dec 20 - Jan 3) | 76.3% | -2.0 pts | 1.2% | 500 |
| Summer peak (Jun 15 - Aug 15) | 70.0% | -8.2 pts | 1.7% | 2,121 |
| All other days | 78.3% | — | 1.0% | 8,926 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).