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

Seattle, WA (SEA) to Chicago, IL (MDW) flight delay odds

79.8% of 678 official scheduled SEA-to-MDW flights arrived on time; 11.1% arrived at least 30 minutes late and 0.6% 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
79.8%arrived on time
11.1%30+ min late
0.6%cancelled
678scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late3.4%all scheduled flights
120+ minutes late0.3%all scheduled flights
Diverted0.6%did not reach as scheduled
Average arrival+0.2 mincompleted flights

Which departure time was most reliable for SEA to MDW?

Among qualifying SEA-to-MDW departure window results, Early morning had the highest on-time rate: 90.9% of 352 flights. Afternoon was lowest at 39.1% across 64 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning35290.9%3.7%0.9%
Late morning5170.6%11.8%2.0%
Afternoon6439.1%40.6%0.0%
Night21175.8%14.2%0.0%

Which weekday was most reliable for SEA to MDW?

Among qualifying SEA-to-MDW weekday results, Saturday had the highest on-time rate: 86.8% of 91 flights. Thursday was lowest at 72.7% across 99 flights.

DayFlightsOn time30+ minCancelled
Monday9980.8%11.1%1.0%
Tuesday10280.4%11.8%0.0%
Wednesday9983.8%9.1%1.0%
Thursday9972.7%12.1%1.0%
Friday9875.5%14.3%0.0%
Saturday9186.8%5.5%1.1%
Sunday9078.9%13.3%0.0%

Which airline was most reliable for SEA to MDW?

Only Southwest Airlines met the SEA-to-MDW airline threshold: 79.8% of 678 scheduled flights arrived on time during July 2025–June 2026.

AirlineFlightsOn time30+ minCancelled
Southwest Airlines67879.8%11.1%0.6%

Which month was most reliable for SEA to MDW?

Among qualifying SEA-to-MDW month results, February 2026 had the highest on-time rate: 100.0% of 28 flights. July 2025 was lowest at 64.8% across 88 flights.

MonthFlightsOn time30+ minCancelled
July 20258864.8%20.5%1.1%
August 20258868.2%15.9%0.0%
September 20258669.8%22.1%0.0%
October 20253397.0%0.0%0.0%
November 20253090.0%0.0%0.0%
December 20253193.5%6.5%0.0%
January 20263196.8%0.0%0.0%
February 202628100.0%0.0%0.0%
March 20265891.4%5.2%3.4%
April 20266080.0%8.3%0.0%
May 20266290.3%3.2%0.0%
June 20268373.5%14.5%1.2%

What drove SEA to MDW delay minutes?

Late aircraft was the largest recorded SEA-to-MDW delay category, accounting for 48.7% of 5,234 BTS-attributed delay minutes during July 2025–June 2026.

Airline34.0%
Late aircraft48.7%
National airspace14.0%
Weather2.2%
Security1.1%
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.