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

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

63.4% of 678 official scheduled MDW-to-SEA flights arrived on time; 18.9% arrived at least 30 minutes late and 0.4% 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 SIGNALVariable
63.4%arrived on time
18.9%30+ min late
0.4%cancelled
678scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late8.6%all scheduled flights
120+ minutes late2.4%all scheduled flights
Diverted0.4%did not reach as scheduled
Average arrival+14.4 mincompleted flights

Which departure time was most reliable for MDW to SEA?

Among qualifying MDW-to-SEA departure window results, Early morning had the highest on-time rate: 74.5% of 98 flights. Afternoon was lowest at 56.0% across 109 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning9874.5%6.1%0.0%
Late morning20668.9%12.6%0.5%
Afternoon10956.0%22.0%0.0%
Evening7258.3%30.6%1.4%
Night19358.0%25.9%0.5%

Which weekday was most reliable for MDW to SEA?

Among qualifying MDW-to-SEA weekday results, Saturday had the highest on-time rate: 69.2% of 91 flights. Friday was lowest at 55.1% across 98 flights.

DayFlightsOn time30+ minCancelled
Monday9963.6%22.2%0.0%
Tuesday10268.6%15.7%0.0%
Wednesday9967.7%16.2%0.0%
Thursday9958.6%20.2%1.0%
Friday9855.1%24.5%1.0%
Saturday9169.2%14.3%1.1%
Sunday9061.1%18.9%0.0%

Which airline was most reliable for MDW to SEA?

Only Southwest Airlines met the MDW-to-SEA airline threshold: 63.4% of 678 scheduled flights arrived on time during July 2025–June 2026.

AirlineFlightsOn time30+ minCancelled
Southwest Airlines67863.4%18.9%0.4%

Which month was most reliable for MDW to SEA?

Among qualifying MDW-to-SEA month results, January 2026 had the highest on-time rate: 87.1% of 31 flights. March 2026 was lowest at 24.1% across 58 flights.

MonthFlightsOn time30+ minCancelled
July 20258856.8%25.0%1.1%
August 20258864.8%10.2%0.0%
September 20258679.1%7.0%0.0%
October 20253381.8%9.1%0.0%
November 20253060.0%16.7%3.3%
December 20253151.6%19.4%0.0%
January 20263187.1%6.5%0.0%
February 20262875.0%7.1%0.0%
March 20265824.1%43.1%1.7%
April 20266073.3%15.0%0.0%
May 20266272.6%11.3%0.0%
June 20268351.8%38.6%0.0%

What drove MDW to SEA delay minutes?

Late aircraft was the largest recorded MDW-to-SEA delay category, accounting for 46.2% of 11,700 BTS-attributed delay minutes during July 2025–June 2026.

Airline24.4%
Late aircraft46.2%
National airspace23.8%
Weather5.0%
Security0.6%
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.