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

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

Historically, 80.6% of scheduled reportable flights on this direction arrived on time in July 2025–June 2026. The sample includes 1,705 flights.

HISTORICAL ROUTE SIGNALLower disruption
80.6%arrived on time
11.5%30+ min late
1.1%cancelled
1,705scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late5.6%all scheduled flights
120+ minutes late2.2%all scheduled flights
Diverted0.1%did not reach as scheduled
Average arrival+2.5 mincompleted flights

When is this route most reliable?

The same route can behave differently through the day. These are scheduled departure windows, not actual departure times. Small time windows with fewer than 40 flights are withheld.

Departure windowFlightsOn time30+ minCancelled
Early morning41293.7%3.6%0.2%
Late morning36087.8%5.3%1.7%
Afternoon38278.8%13.4%1.0%
Evening38269.1%18.1%1.3%
Night16963.9%24.9%1.2%

Weekday comparison

Day-of-week results use at least 30 scheduled flights per row. Look for broad patterns, not tiny percentage differences.

DayFlightsOn time30+ minCancelled
Monday26276.0%17.2%0.8%
Tuesday26986.2%7.4%0.4%
Wednesday26085.0%6.5%1.5%
Thursday25679.7%9.8%0.4%
Friday25781.7%10.9%1.2%
Saturday16680.1%12.0%2.4%
Sunday23574.9%17.4%1.3%

Airline comparison

Marketing-carrier results make codeshare flights easier to compare as travelers buy them. Dedicated route-airline reports require at least 160 flights.

AirlineFlightsOn time30+ minCancelled
Southwest Airlines1,70580.6%11.5%1.1%

Monthly trend

Month-by-month results show whether a twelve-month average hides an unusual period.

MonthFlightsOn time30+ minCancelled
July 202516970.4%17.2%1.2%
August 202515483.8%9.7%0.6%
September 202515192.7%2.6%0.0%
October 202513086.9%8.5%0.0%
November 202512782.7%7.1%3.1%
December 202513977.7%15.8%0.7%
January 202612084.2%11.7%0.0%
February 202611088.2%7.3%0.0%
March 202613672.1%16.9%2.9%
April 202615184.1%10.6%1.3%
May 202615678.2%10.9%0.6%
June 202616271.6%17.3%1.9%

What drove reported delay minutes?

BTS cause minutes are reported for qualifying delayed flights. These shares describe recorded delay minutes—not the chance that a particular cause will affect your next flight.

Airline33.3%
Late aircraft53.8%
National airspace10.7%
Weather2.1%
Security0.0%
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.