Best Time to Fly ORD to STL: On-Time Stats by Hour & Airline
Chicago O'Hare International → St Louis Lambert International
Data through July 2026 · Last updated October 18, 2026
3,090 flights were scheduled from Chicago (ORD) to St. Louis (STL) in the last 12 months, and 72.1% of those that flew arrived on time, 5.6 points below the US average of 77.6%.
Republic Airways was the most punctual of the 5 airlines on the route at 76.2%, while American Airlines trailed at 66.1%.
September has been the best month (84% on time) and Sunday the weakest day of the week (70%).
2.9% of flights were cancelled, versus 1.8% nationally.
ORD to STL 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 |
|---|---|---|---|---|
| Republic Airways | 76.2% | 78 min | 3.0% | 434 |
| Envoy Air | 75.5% | 52 min | 2.7% | 782 |
| United Airlines | 73.0% | 75 min | 1.4% | 560 |
| SkyWest Airlines | 69.5% | 72 min | 4.3% | 809 |
| American Airlines | 66.1% | 90 min | 2.8% | 505 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly ORD to STL
On-time arrival % by scheduled departure hour (local time), 5,865 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 75.2% | 2.5% | 159 |
| 7am–8am | 86.8% | 1.2% | 247 |
| 8am–9am | 81.5% | 1.7% | 352 |
| 9am–10am | 84.4% | 0.3% | 308 |
| 10am–11am | 81.2% | 1.7% | 299 |
| 11am–12pm | 78.7% | 1.4% | 283 |
| 12pm–1pm | 80.2% | 2.5% | 481 |
| 1pm–2pm | 84.5% | 1.3% | 458 |
| 2pm–3pm | 76.4% | 1.3% | 998 |
| 3pm–4pm | 79.8% | 1.2% | 245 |
| 4pm–5pm | 77.9% | 3.1% | 351 |
| 5pm–6pm | 52.8% | 4.0% | 224 |
| 6pm–7pm | 64.7% | 4.6% | 303 |
| 7pm–8pm | 64.2% | 1.1% | 348 |
| 8pm–9pm | 67.7% | 1.5% | 336 |
| 9pm–10pm | 53.9% | 1.9% | 104 |
| 10pm–11pm | 61.3% | 3.2% | 310 |
| 11pm–12am | 61.1% | 8.5% | 59 |
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 STL
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) | 68.5% | -8.2 pts | 10.7% | 103 |
| Christmas & New Year (Dec 20 - Jan 3) | 72.3% | -4.4 pts | 1.2% | 161 |
| Summer peak (Jun 15 - Aug 15) | 69.8% | -6.9 pts | 1.4% | 1,182 |
| All other days | 76.7% | — | 2.0% | 4,419 |
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).