STL to MDW flight delays & on-time performance
Nonstop flights from St. Louis Lambert International Airport to Chicago Midway International Airport · 251 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at STL or MDW right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from St. Louis (STL) to Chicago (MDW) arrived on time 80% of the time in Aug 2025 – Jul 2026, better than the 78% national average.
- 1.2% were cancelled, and 5% arrived an hour or more late.
- Southwest Airlines is the only airline reporting nonstop flights on this route.
- Departures scheduled around 6am did best (97% on time); around 4pm did worst (59%).
- Tuesday was the most reliable day to fly (88% on time) and Monday the least (77%).
- The largest source of delay minutes was late-arriving aircraft (49%).
Which airline is most on time from STL to MDW?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Southwest Airlines | 80% | 1.2% | 12 min | 5.3% | 1,704 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am92%201 flights
- 6am97%67 flights
- 7am86%132 flights
- 8am91%111 flights
- 9am85%53 flights
- 10am86%104 flights
- 11am83%72 flights
- 12pm65%32 flights
- 1pm86%137 flights
- 2pm89%100 flights
- 3pm76%56 flights
- 4pm59%186 flights
- 5pm72%92 flights
- 6pm64%89 flights
- 7pm74%57 flights
- 8pm82%95 flights
- 9pm67%100 flights
- 10pm70%20 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday77%2.3% cancelled
- Tuesday88%0.4% cancelled
- Wednesday81%0.8% cancelled
- Thursday77%0.8% cancelled
- Friday80%1.9% cancelled
- Saturday78%1.2% cancelled
- Sunday78%1.3% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft49%
- Airline (crew, maintenance, cleaning, fueling)28%
- Air traffic control & airport congestion21%
- Extreme weather3%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather62%
- Airline (crew, maintenance, cleaning, fueling)29%
- Air traffic control & airport congestion10%
- Security0%
STL to MDW: common questions
- How often are STL to MDW flights on time?
- 80% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from St. Louis to Chicago cancelled?
- 1.2% of scheduled flights were cancelled (21 of 1,704).
- How long are typical delays?
- Across all flights the average arrival delay was 12 min (early arrivals count as zero). Flights that were late arrived 52 min behind schedule on average, and 5.3% of flights were an hour or more late.
- How long is taxi time at STL?
- Flights on this route spent 12 min taxiing from the gate to takeoff on average.
Related routes
Return trip: MDW to STL — 82% on time
More flights from St. Louis
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: STL → MDW, nonstop flights by US airlines that report to the DOT. How we calculate this.