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

Ontario, CA (ONT) to Chicago, IL (MDW) flight delay odds

89.2% of 360 official scheduled ONT-to-MDW flights arrived on time; 5.3% arrived at least 30 minutes late and 0.3% 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 SIGNALLower disruption
89.2%arrived on time
5.3%30+ min late
0.3%cancelled
360scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late1.9%all scheduled flights
120+ minutes late0.6%all scheduled flights
Diverted0.6%did not reach as scheduled
Average arrival-3.2 mincompleted flights

Which departure time was most reliable for ONT to MDW?

Among qualifying ONT-to-MDW departure window results, Early morning had the highest on-time rate: 91.4% of 197 flights. Night was lowest at 87.3% across 118 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning19791.4%4.6%0.5%
Night11887.3%5.9%0.0%

Which weekday was most reliable for ONT to MDW?

Among qualifying ONT-to-MDW weekday results, Sunday had the highest on-time rate: 96.2% of 52 flights. Monday was lowest at 84.6% across 52 flights.

DayFlightsOn time30+ minCancelled
Monday5284.6%11.5%0.0%
Tuesday5390.6%3.8%0.0%
Wednesday5288.5%5.8%0.0%
Thursday5288.5%5.8%0.0%
Friday5288.5%0.0%0.0%
Saturday4787.2%8.5%2.1%
Sunday5296.2%1.9%0.0%

Which airline was most reliable for ONT to MDW?

Only Southwest Airlines met the ONT-to-MDW airline threshold: 89.2% of 360 scheduled flights arrived on time during July 2025–June 2026.

AirlineFlightsOn time30+ minCancelled
Southwest Airlines36089.2%5.3%0.3%

Which month was most reliable for ONT to MDW?

Among qualifying ONT-to-MDW month results, October 2025 had the highest on-time rate: 100.0% of 31 flights. June 2026 was lowest at 80.0% across 30 flights.

MonthFlightsOn time30+ minCancelled
July 20253183.9%9.7%0.0%
August 20253190.3%3.2%0.0%
September 20253096.7%3.3%0.0%
October 202531100.0%0.0%0.0%
November 20253086.7%10.0%3.3%
December 20253187.1%6.5%0.0%
January 20262788.9%3.7%0.0%
February 20262785.2%3.7%0.0%
March 20263193.5%6.5%0.0%
April 20263080.0%10.0%0.0%
May 20263196.8%3.2%0.0%
June 20263080.0%3.3%0.0%

What drove ONT to MDW delay minutes?

Airline was the largest recorded ONT-to-MDW delay category, accounting for 46.2% of 1,491 BTS-attributed delay minutes during July 2025–June 2026.

Airline46.2%
Late aircraft29.4%
National airspace24.4%
Weather0.0%
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.