Best Time to Fly IAH to ORD: On-Time Stats by Hour & Airline
George Bush Intercontinental/Houston → Chicago O'Hare International
Data through July 2026 · Last updated October 18, 2026
6,119 flights were scheduled from Houston (IAH) to Chicago (ORD) in the last 12 months, and 75.2% of those that flew arrived on time, 2.4 points below the US average of 77.6%.
United Airlines was the most punctual of the 6 airlines on the route at 78.6%, while Spirit Airlines trailed at 63.3%.
September has been the best month (87% on time) and Sunday the weakest day of the week (73%).
1.6% of flights were cancelled, versus 1.8% nationally.
IAH to ORD 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 | 78.6% | 70 min | 0.7% | 4,048 |
| Envoy Air | 73.3% | 63 min | 1.1% | 354 |
| Republic Airways | 73.3% | 81 min | 3.6% | 365 |
| American Airlines | 67.1% | 121 min | 3.6% | 812 |
| Frontier Airlines | 65.2% | 137 min | 4.2% | 262 |
| Spirit Airlines | 63.3% | 71 min | 4.8% | 272 |
| PSA Airlines | Limited data | 4 | ||
| SkyWest Airlines | Limited data | 2 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAH to ORD
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 | 94.1% | 1.1% | 567 |
| 6am–7am | 87.4% | 2.2% | 1,416 |
| 7am–8am | 89.6% | 1.1% | 817 |
| 8am–9am | 91.0% | 0.7% | 765 |
| 9am–10am | 86.3% | 0.4% | 742 |
| 10am–11am | 77.3% | 1.1% | 464 |
| 11am–12pm | 73.2% | 1.0% | 707 |
| 12pm–1pm | 83.4% | 1.5% | 392 |
| 1pm–2pm | 71.3% | 1.1% | 643 |
| 2pm–3pm | 76.0% | 0.6% | 820 |
| 3pm–4pm | 61.5% | 0.0% | 52 |
| 4pm–5pm | 59.1% | 2.9% | 615 |
| 5pm–6pm | 62.1% | 1.2% | 743 |
| 6pm–7pm | 60.1% | 1.6% | 1,128 |
| 7pm–8pm | 67.6% | 1.1% | 178 |
| 8pm–9pm | 73.2% | 0.7% | 768 |
| 9pm–10pm | 76.7% | 2.0% | 711 |
| 10pm–11pm | 77.8% | 2.6% | 230 |
| 11pm–12am | Limited data | 4 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on IAH to ORD
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) | 71.5% | -7.6 pts | 4.2% | 216 |
| Christmas & New Year (Dec 20 - Jan 3) | 73.5% | -5.6 pts | 0.6% | 498 |
| Summer peak (Jun 15 - Aug 15) | 70.3% | -8.8 pts | 1.8% | 2,118 |
| All other days | 79.1% | — | 1.2% | 8,931 |
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).