St. Louis (STL) to Chicago (ORD): On-Time Performance
Data through July 2026
When you fly STL to ORD matters as much as anything else about the booking: the route swung from 85% on-time in October 2024 to just 61% in July 2025. Across the full period the route averages 74% on-time against a national 78%. Morning departures also hold up better than evening ones (83% vs 61%), which matters most in the rough months.
- On-time
- 74%
- arrived <15 min late
- Avg delay
- 24 min
- completed flights
- Cancelled
- 2.4%
- Flights/day
- 8.5
- last 12 months
- Duration
- 1h 26m
- scheduled
- Distance
- 258 mi
Best airline from STL to ORD
5 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| American Airlinesmost reliable | 82% | 24 min | 1.9% | 1,189 |
| Republic Airways | 79% | 16 min | 3.5% | 925 |
| Envoy Air | 76% | 20 min | 2.1% | 1,544 |
| United Airlines | 67% | 27 min | 1.2% | 1,158 |
| SkyWest Airlines | 66% | 34 min | 3.5% | 1,288 |
Monthly on-time trend
Best time to fly from STL to ORD
Aim for departures around 5 a.m. (91% on-time); avoid 8 p.m. departures (51%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 74% | 34 min |
| Tuesday | 77% | 19 min |
| Wednesday | 75% | 21 min |
| Thursday | 73% | 24 min |
| Friday | 70% | 30 min |
| Saturdaybest | 78% | 19 min |
| Sunday | 72% | 23 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft31%
- Airline operations32%
- National airspace system30%
- Weather8%
Frequently asked questions
- How often are flights from STL to ORD delayed?
- 26% of STL–ORD flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 24 minutes.
- Which airline is most reliable from STL to ORD?
- American Airlines has the best on-time record on this route at 82%, based on 1,189 flights. 5 airlines flew STL–ORD frequently enough to compare in this period.
- What is the best time of day to fly from STL to ORD?
- Departures around 5 a.m. have the best record (91% on-time), while departures around 8 p.m. have the worst (51%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from STL to ORD?
- The scheduled STL–ORD flight time averages 1h 26m over 258 miles. Actual arrival times vary — flights on this route land 15+ minutes late 26% of the time.
- How often are STL to ORD flights cancelled?
- 2.4% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, slightly above the national rate of 1.6%.
- What is the worst month to fly from STL to ORD?
- July 2025 was the roughest month in this dataset, with only 61% of arrivals on time. The best was October 2024 at 85%. If your dates are flexible, that 24-point gap is worth planning around.
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Based on 6,104 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.