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Route Reliability

St. Louis → Chicago

STL–MDW · 251 miles · St. Louis Lambert International Airport to Chicago Midway International Airport

84
Pretty Reliable
WanderNerd Reliability Score
81%
Arrive within 15 minutes
4 min
Average arrival delay
1.1%
Cancelled
1,706
Flights in the data

Data through May 2026.

Southwest Airlines is the only airline in this data on this route, arriving on time 81% of the time across 1,706 flights. No comparison to make.

What the data says

Morning flights do better here.

STL–MDW flights departing between 3–6 AM arrived on time 94% of the time, versus 66% between 9 PM–12 AM.

Thursday is the weak spot.

STL–MDW flights arrived on time 89% of the time on Tuesdays. On Thursdays: 76%.

Slipping a little lately.

STL–MDW flights arrived on time 81% of the time over the last three months in the data, compared with 85% in the three months before that.

Flights on this route

The breakdown

On-time by weekday
  • Mon79%(257 flights)
  • Tue89%(264 flights)
  • Wed84%(257 flights)
  • Thu76%(253 flights)
  • Fri82%(254 flights)
  • Sat80%(162 flights)
  • Sun78%(238 flights)
On-time by departure window
  • 3–6 AM94%(189 flights)
  • 6–9 AM91%(331 flights)
  • 9 AM–12 PM86%(226 flights)
  • 12–3 PM88%(240 flights)
  • 3–6 PM69%(330 flights)
  • 6–9 PM71%(292 flights)
  • 9 PM–12 AM66%(77 flights)
On-time trend by month
84%
May

Jun 80% → May 84% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202580%161
July 202570%167
August 202576%151
September 202585%151
October 202583%130
November 202590%122
December 202578%138
January 202688%120
February 202690%111
March 202673%131
April 202685%148
May 202684%155

Same trip, other airports

Keep nerding

Based on 1,706 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.