Ontario (ONT) to Chicago (MDW): On-Time Performance
Data through May 2026
Ontario (ONT) to Chicago (MDW) is a thinner route than most in this dataset — 360 departures over the past year, roughly 7 a week — so treat these numbers as indicative rather than definitive. Of the flights that did operate, 90% arrived on time, comfortably above the national average of 78%.
- On-time
- 90%
- arrived <15 min late
- Avg delay
- 5 min
- completed flights
- Cancelled
- 0.3%
- Flights/day
- 0.99
- last 12 months
- Duration
- 3h 48m
- scheduled
- Distance
- 1,706 mi
Monthly on-time trend
Best time to fly from ONT to MDW
Aim for departures around 9 a.m. (97% on-time); avoid 11 a.m. departures (87%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 88% | 7 min |
| Tuesdaybest | 92% | 4 min |
| Wednesday | 87% | 5 min |
| Thursday | 89% | 5 min |
| Friday | 90% | 3 min |
| Saturday | 89% | 7 min |
| Sunday | 92% | 5 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft31%
- Airline operations48%
- National airspace system21%
- Security1%
Frequently asked questions
- How often are flights from ONT to MDW delayed?
- 10% of ONT–MDW flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 5 minutes.
- What is the best time of day to fly from ONT to MDW?
- Departures around 9 a.m. have the best record (97% on-time), while departures around 11 a.m. have the worst (87%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from ONT to MDW?
- The scheduled ONT–MDW flight time averages 3h 48m over 1,706 miles. Actual arrival times vary — flights on this route land 15+ minutes late 10% of the time.
- How often are ONT to MDW flights cancelled?
- 0.3% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from ONT to MDW?
- April 2026 was the roughest month in this dataset, with only 80% of arrivals on time. The best was April 2025 at 100%. If your dates are flexible, that 20-point gap is worth planning around.
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Based on 723 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.