Chicago (MDW) to St. Louis (STL): On-Time Performance
Data through July 2026
The calendar drives reliability on MDW–STL. October 2024 flights landed on schedule 94% of the time, but July 2025 dropped to 71% — a gap of 23 points. Across the full period the route averages 83% on-time against a national 78%. Morning departures also hold up better than evening ones (93% vs 72%), which matters most in the rough months.
- On-time
- 83%
- arrived <15 min late
- Avg delay
- 10 min
- completed flights
- Cancelled
- 1.1%
- Flights/day
- 4.7
- last 12 months
- Duration
- 1h 13m
- scheduled
- Distance
- 251 mi
Monthly on-time trend
Best time to fly from MDW to STL
Aim for departures around 5 a.m. (100% on-time); avoid 9 p.m. departures (66%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 80% | 14 min |
| Tuesdaybest | 87% | 8 min |
| Wednesday | 87% | 8 min |
| Thursday | 83% | 10 min |
| Friday | 82% | 11 min |
| Saturday | 85% | 8 min |
| Sunday | 80% | 12 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft54%
- Airline operations34%
- National airspace system10%
- Weather2%
Frequently asked questions
- How often are flights from MDW to STL delayed?
- 17% of MDW–STL 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 10 minutes.
- What is the best time of day to fly from MDW to STL?
- Departures around 5 a.m. have the best record (100% on-time), while departures around 9 p.m. have the worst (66%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from MDW to STL?
- The scheduled MDW–STL flight time averages 1h 13m over 251 miles. Actual arrival times vary — flights on this route land 15+ minutes late 17% of the time.
- How often are MDW to STL flights cancelled?
- 1.1% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from MDW to STL?
- July 2025 was the roughest month in this dataset, with only 71% of arrivals on time. The best was October 2024 at 94%. If your dates are flexible, that 23-point gap is worth planning around.
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Based on 3,702 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.