San Francisco (SFO) to Chicago (MDW): On-Time Performance
Data through July 2026
When you fly SFO to MDW matters as much as anything else about the booking: the route swung from 90% on-time in December 2024 to just 60% in July 2026. Across the full period the route averages 77% on-time against a national 78%. Morning departures also hold up better than evening ones (84% vs 48%), which matters most in the rough months.
- On-time
- 77%
- arrived <15 min late
- Avg delay
- 11 min
- completed flights
- Cancelled
- 0.9%
- Flights/day
- 1.3
- last 12 months
- Duration
- 4h 7m
- scheduled
- Distance
- 1,855 mi
Monthly on-time trend
Best time to fly from SFO to MDW
Aim for departures around 6 a.m. (93% on-time); avoid 11 p.m. departures (48%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 80% | 11 min |
| Tuesdaybest | 85% | 5 min |
| Wednesday | 79% | 9 min |
| Thursday | 76% | 13 min |
| Friday | 72% | 13 min |
| Saturday | 81% | 7 min |
| Sunday | 66% | 17 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft61%
- Airline operations22%
- National airspace system15%
- Security1%
Frequently asked questions
- How often are flights from SFO to MDW delayed?
- 23% of SFO–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 11 minutes.
- What is the best time of day to fly from SFO to MDW?
- Departures around 6 a.m. have the best record (93% on-time), while departures around 11 p.m. have the worst (48%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SFO to MDW?
- The scheduled SFO–MDW flight time averages 4h 7m over 1,855 miles. Actual arrival times vary — flights on this route land 15+ minutes late 23% of the time.
- How often are SFO to MDW flights cancelled?
- 0.9% 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 SFO to MDW?
- July 2026 was the roughest month in this dataset, with only 60% of arrivals on time. The best was December 2024 at 90%. If your dates are flexible, that 30-point gap is worth planning around.
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Based on 940 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.