Best Time to Fly SFO to MDW: On-Time Stats by Hour & Airline
San Francisco International → Chicago Midway International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 72.8% of San Francisco (SFO) to Chicago (MDW) flights arrived on time (485 scheduled flights). That is 4.8 points below the national average of 77.6%.
Southwest Airlines was the only reporting airline with regular flights on this route.
November has been the best month (88% on time) and Sunday the weakest day of the week (65%).
1.2% of flights were cancelled, versus 1.8% nationally.
SFO to MDW on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlines | 72.8% | 41 min | 1.2% | 485 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SFO to MDW
On-time arrival % by scheduled departure hour (local time), 868 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 89.7% | 2.4% | 170 |
| 6am–7am | 93.0% | 0.5% | 215 |
| 7am–8am | 90.9% | 1.8% | 56 |
| 8am–9am | 87.3% | 0.0% | 71 |
| 9am–10am | 75.6% | 0.0% | 45 |
| 10am–11am | 60.3% | 0.0% | 122 |
| 12pm–1pm | Limited data | 18 | |
| 1pm–2pm | Limited data | 22 | |
| 11pm–12am | 49.0% | 1.3% | 149 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SFO to MDW
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | Limited data | 13 | ||
| Christmas & New Year (Dec 20 - Jan 3) | 93.3% | +15.9 pts | 0.0% | 30 |
| Summer peak (Jun 15 - Aug 15) | 72.1% | -5.4 pts | 1.1% | 184 |
| All other days | 77.4% | — | 0.9% | 641 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).