Boston (BOS) to Chicago (MDW): On-Time Performance
Data through July 2026
Boston (BOS) to Chicago (MDW) effectively runs on two schedules. In March 2025, 94% of arrivals were on time; in September 2025 that fell to 57% — a 37-point seasonal swing. Across the full period the route averages 75% on-time against a national 78%. Morning departures also hold up better than evening ones (92% vs 51%), which matters most in the rough months.
- On-time
- 75%
- arrived <15 min late
- Avg delay
- 17 min
- completed flights
- Cancelled
- 1.3%
- Flights/day
- 3.7
- last 12 months
- Duration
- 2h 42m
- scheduled
- Distance
- 861 mi
Monthly on-time trend
Best time to fly from BOS to MDW
Aim for departures around 10 a.m. (95% on-time); avoid 8 p.m. departures (40%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 73% | 21 min |
| Tuesday | 77% | 17 min |
| Wednesdaybest | 80% | 11 min |
| Thursday | 72% | 17 min |
| Friday | 75% | 16 min |
| Saturday | 80% | 13 min |
| Sunday | 71% | 21 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft58%
- Airline operations22%
- National airspace system18%
- Weather3%
Frequently asked questions
- How often are flights from BOS to MDW delayed?
- 25% of BOS–MDW flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 17 minutes.
- What is the best time of day to fly from BOS to MDW?
- Departures around 10 a.m. have the best record (95% on-time), while departures around 8 p.m. have the worst (40%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from BOS to MDW?
- The scheduled BOS–MDW flight time averages 2h 42m over 861 miles. Actual arrival times vary — flights on this route land 15+ minutes late 25% of the time.
- How often are BOS to MDW flights cancelled?
- 1.3% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from BOS to MDW?
- September 2025 was the roughest month in this dataset, with only 57% of arrivals on time. The best was March 2025 at 94%. If your dates are flexible, that 37-point gap is worth planning around.
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Based on 2,855 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.