PlainFlights

Route · STL → MDW · 2020–2025 BTS data

St. Louis to Chicago

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), STL to MDW (St. Louis to Chicago) ranks #1064 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

84.8%
On-time
+5.8 pts
vs US avg
59 min
Delay when late
10,793
Flights
#1064 of 4927
Corpus placement

Cancelled

1.4%

Best Month

Feb 2024 95%

Worst Month

Jul 2025 69%

Distance

251 mi

Carriers

1

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 139 30 1 0 WN
Nov 2025 127 12 5 0 WN
Oct 2025 130 25 0 0 WN
Sep 2025 151 25 0 0 WN
Aug 2025 152 36 1 0 WN
Jul 2025 169 53 1 1 WN
Jun 2025 163 33 1 1 WN
May 2025 166 29 2 0 WN
Apr 2025 160 27 0 0 WN
Mar 2025 143 19 0 1 WN
Feb 2025 112 9 3 1 WN
Jan 2025 126 14 9 0 WN
Dec 2024 150 18 0 0 WN
Nov 2024 144 12 0 0 WN
Oct 2024 156 13 1 0 WN
Sep 2024 161 14 1 0 WN
Aug 2024 170 25 1 1 WN
Jul 2024 182 48 3 0 WN
Jun 2024 173 38 0 0 WN
May 2024 155 38 1 2 WN
Apr 2024 153 19 1 0 WN
Mar 2024 156 20 1 0 WN
Feb 2024 129 7 1 0 WN
Jan 2024 146 26 17 1 WN

STL–MDW seasonal on-time pattern

Best: February (92.1%) · weakest: July (77.7%)

75%80%85%90%95% JanFebMarAprMayJunJulAugSepOctNovDec 82.9%

Strongest calendar month

February

92.1% on-time · ~123 flights/mo

Busiest calendar month

July

~180 flights/mo avg

Weakest calendar month

July

77.7% on-time · ~180 flights/mo

Cancellation Rate

1.4%

50 of 3,613 flights

Diversion Rate

0.2%

8 of 3,613 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

STL - St. Louis

Full on-time, delay-cause, and seasonal performance for St. Louis, MO.

STL on-time profile

MDW - Chicago

Full on-time, delay-cause, and seasonal performance for Chicago, IL.

MDW on-time profile

Compare the two airports

See STL and MDW side by side on delays, cancellations, and reliability.

Compare STL vs MDW

Origin-hub reliability standing

Mid-pack among STL departures

From STL, this corridor sits with 45 other 75–85% on-time routes out of 51 tracked departures, not the hub's reliability leaders (5 at ≥85%) and not the softest ( 1 below 75%). Destination: Chicago · fleet on-time rank #1315 of 4927.

What the Data Says About STL to MDW

Bureau of Transportation Statistics records show St. Louis to Chicago (STL to MDW) running a 84.8% on-time rate over 10,793 tracked flights, on the stronger end of a typical domestic pairing. When flights do run late, the average delay is 59.0 minutes. The 251-mile corridor is served by 1 carrier, and over the last 24 months 1.4% of 3,613 flights were cancelled, 0.2% diverted.

The monthly split is wide on this route: Feb 2024 posted the strongest performance at 95% on-time, while Jul 2025 came in at just 69% - a 26-point swing worth factoring into travel timing.

On the multi-year calendar, STL–MDW peaks in February at 92.1% on-time while July carries the heaviest traffic (~180 flights per month) ; the softest month is July at 77.7%, a 14.4-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does STL to MDW rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, STL to MDW ranks #1064 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from STL to MDW? ▼
Flights from St. Louis to Chicago have a 84.8% on-time rate based on 10,793 flights. The average delay is 59.0 minutes. The best recent month was Feb 2024 with 95% on-time.
What is the cancellation rate for STL to MDW? ▼
Over the last 24 months, 1.4% of flights on this route were cancelled (50 of 3,613 flights) and 0.2% were diverted.
How far is the flight from STL to MDW? ▼
The flight distance from St. Louis (STL) to Chicago (MDW) is approximately 251 miles. This route is served by 1 carrier.
When is the best time to fly from STL to MDW? ▼
The best recent month for on-time performance was Feb 2024 (95% on-time). The worst was Jul 2025 (69% on-time). Consider booking during months with historically better performance.

Airports on this route

STL Airport

St. Louis
MDW Airport

Chicago
Data source

Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.

Read our methodology - how this data is sourced, computed, and verified.

Using STL–MDW data

STL–MDW runs 5.8 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare STL and MDW airport profiles: delay causes and top routes differ even on the same corridor. STL airport
  • If your dates flex, February (92.1% on-time) beats July (77.7%) on this corridor. Seasonal chart
  • 4 other routes post a similar 84.8% on-time rate; compare before you commit to this pairing. Similar routes

On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.