Best Time to Fly STL to ORD: On-Time Stats by Hour & Airline
St Louis Lambert International → Chicago O'Hare International
Data through July 2026 · Last updated October 18, 2026
3,090 flights were scheduled from St. Louis (STL) to Chicago (ORD) in the last 12 months, and 72.6% of those that flew arrived on time, 5.0 points below the US average of 77.6%.
American Airlines was the most punctual of the 5 airlines on the route at 81.3%, while SkyWest Airlines trailed at 63.9%.
February has been the best month (83% on time) and Friday the weakest day of the week (70%).
3.6% of flights were cancelled, versus 1.8% nationally.
STL 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 |
|---|---|---|---|---|
| American Airlines | 81.3% | 135 min | 2.6% | 502 |
| Envoy Air | 75.4% | 93 min | 2.9% | 783 |
| Republic Airways | 74.9% | 77 min | 4.8% | 437 |
| United Airlines | 71.6% | 80 min | 2.1% | 557 |
| SkyWest Airlines | 63.9% | 105 min | 5.1% | 811 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly STL to ORD
On-time arrival % by scheduled departure hour (local time), 5,866 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 91.0% | 1.1% | 260 |
| 6am–7am | 87.7% | 1.6% | 511 |
| 7am–8am | 80.1% | 1.8% | 492 |
| 8am–9am | 76.7% | 1.9% | 359 |
| 9am–10am | 86.2% | 1.5% | 332 |
| 10am–11am | 81.2% | 1.8% | 168 |
| 11am–12pm | 82.5% | 0.7% | 304 |
| 12pm–1pm | 73.3% | 1.2% | 164 |
| 1pm–2pm | 70.1% | 1.6% | 544 |
| 2pm–3pm | 70.8% | 3.4% | 291 |
| 3pm–4pm | 73.2% | 2.9% | 561 |
| 4pm–5pm | 69.6% | 3.8% | 393 |
| 5pm–6pm | 64.2% | 1.8% | 779 |
| 6pm–7pm | 66.1% | 4.3% | 349 |
| 7pm–8pm | 58.3% | 7.1% | 168 |
| 8pm–9pm | 51.7% | 7.4% | 189 |
| 9pm–10pm | Limited data | 2 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on STL 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) | 51.6% | -24.5 pts | 7.8% | 103 |
| Christmas & New Year (Dec 20 - Jan 3) | 76.7% | +0.7 pts | 1.2% | 161 |
| Summer peak (Jun 15 - Aug 15) | 69.0% | -7.0 pts | 2.4% | 1,181 |
| All other days | 76.0% | — | 2.4% | 4,421 |
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).