BTS DATA COMPLETE THROUGH JUNE 2026HISTORICAL ODDS · NOT LIVE FLIGHT STATUS
DelayOddsKnow the route before you book
STL→MDW

St. Louis, MO (STL) to Chicago, IL (MDW) flight delay odds

78.7% of 1,704 official scheduled STL-to-MDW flights arrived on time; 12.6% arrived at least 30 minutes late and 1.1% were cancelled during July 2025–June 2026.

Source: U.S. Bureau of Transportation Statistics · Reporting window: July 2025–June 2026 · Updated September 16, 2026

HISTORICAL ROUTE SIGNALGenerally reliable
78.7%arrived on time
12.6%30+ min late
1.1%cancelled
1,704scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late5.7%all scheduled flights
120+ minutes late1.9%all scheduled flights
Diverted0.2%did not reach as scheduled
Average arrival+4.3 mincompleted flights

Which departure time was most reliable for STL to MDW?

Among qualifying STL-to-MDW departure window results, Early morning had the highest on-time rate: 90.0% of 520 flights. Night was lowest at 67.0% across 97 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning52090.0%4.4%1.2%
Late morning23083.5%8.3%2.2%
Afternoon49773.6%15.3%1.0%
Evening36069.4%20.3%0.6%
Night9767.0%23.7%1.0%

Which weekday was most reliable for STL to MDW?

Among qualifying STL-to-MDW weekday results, Tuesday had the highest on-time rate: 86.7% of 270 flights. Thursday was lowest at 72.8% across 254 flights.

DayFlightsOn time30+ minCancelled
Monday26374.1%17.5%1.5%
Tuesday27086.7%7.8%0.4%
Wednesday25882.9%8.1%0.8%
Thursday25472.8%13.8%0.8%
Friday25879.5%12.4%1.6%
Saturday16577.6%14.5%1.8%
Sunday23676.3%14.8%1.3%

Which airline was most reliable for STL to MDW?

Only Southwest Airlines met the STL-to-MDW airline threshold: 78.7% of 1,704 scheduled flights arrived on time during July 2025–June 2026.

AirlineFlightsOn time30+ minCancelled
Southwest Airlines1,70478.7%12.6%1.1%

Which month was most reliable for STL to MDW?

Among qualifying STL-to-MDW month results, February 2026 had the highest on-time rate: 90.1% of 111 flights. July 2025 was lowest at 67.5% across 169 flights.

MonthFlightsOn time30+ minCancelled
July 202516967.5%22.5%0.6%
August 202515275.7%14.5%0.7%
September 202515183.4%7.9%0.0%
October 202513080.8%6.2%0.0%
November 202512786.6%6.3%3.9%
December 202513977.7%15.1%0.7%
January 202612186.0%9.9%0.8%
February 202611190.1%6.3%0.0%
March 202613669.1%19.9%3.7%
April 202615082.7%10.0%0.7%
May 202615782.8%9.6%1.3%
June 202616168.9%18.0%1.2%

What drove STL to MDW delay minutes?

Late aircraft was the largest recorded STL-to-MDW delay category, accounting for 49.3% of 18,454 BTS-attributed delay minutes during July 2025–June 2026.

Airline26.3%
Late aircraft49.3%
National airspace20.6%
Weather3.7%
Security0.1%
This is historical evidence, not a forecast.

Weather, schedules and operations change. For a trip you have already booked, use the airline or airport for live status.