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

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

Historically, 63.4% of scheduled reportable flights on this direction arrived on time in July 2025–June 2026. The sample includes 678 flights.

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

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 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%

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
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%

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 Airlines67863.4%18.9%0.4%

Monthly trend

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

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 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.

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.