Route profile
SFO→MDW
Flight reliability, delays and best times to fly from San Francisco to Chicago, 1,855 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 53% of comparable major US routes (4,598 compared)
Calculated from 1,247 flights. How this is calculated · What counts as on time
SFO → MDW arrives on time 74.8% of the time; the return trip, MDW → SFO, arrives on time 56.3% of the time, an 18.4-point gap between the two directions of the same city pair.
SFO → MDW spends 21.8 minutes on the ground on a 1,855-mile trip: 16.6 minutes from pushback to wheels-up at SFO and 5.2 minutes from touchdown to gate at MDW.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
On-time performance swings unusually widely by time of day here, wider than 99% of 4,023 comparable routes.
89.4% on time for 5–9 AM departures, against 49.0% for 9 PM–5 AM.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,023 in the comparison.
What sets this route apart
Where SFO to MDW differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
SFO to MDW struggles most at 11 PM: 49.0% of its flights scheduled then arrive on time, 32 points behind the 81.0% on routes of similar length at the same hour. Against all other routes the gap is 30.1 points.
Wednesday is the day SFO to MDW slips furthest against routes of similar length, 73.4% on time where they average 80.6%, 7.2 points lower. Against all other routes the gap is 7.4 points.
SFO to MDW against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 11 PM departures | 49.0% | routes of similar length | 81.0% | −32.0 pts | 145 here, 63,823 there |
| Weekday: Wednesday | 73.4% | routes of similar length | 80.6% | −7.2 pts | 169 here, 168,424 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,855 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
40 min late
against a median of 2 min early
Percentiles over 1,247 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at MDW after arriving from SFO.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 46% | Likely to miss |
| 45 min | 24% | High risk |
| 60 min | 15% | Some risk |
| 90 min | 6.6% | Some risk |
| 120 min | 2.9% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.72% of the time and diverts 0.48% of the time, which a late arrival never shows up in.
Chance of missing is the share of 1,232 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 40 minutes late (90th-percentile gate arrival delay), over 1,247 operations.
Any other layover length: connection checker.
Best time to fly
SFO → MDW flights departing 5–9 AM arrived on time 89.4% of the time, against 49.0% for 9 PM–5 AM departures, a gap of 40.4 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 88.8% on time from 211 flights
- 6 AM: 93.5% on time from 232 flights
- 7 AM: too few flights to score
- 8 AM: 84.1% on time from 165 flights
- 9 AM: too few flights to score
- 10 AM: 60.3% on time from 122 flights
- 11 AM to 10 PM: too few flights to score
- 11 PM: 49.0% on time from 149 flights
Departure windows with fewer than 120 flights are not scored.
Why SFO → MDW runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for SFO → MDW. Only delays of 15 minutes or more are attributed. What the five causes mean
Late-arriving aircraft is the largest cause on SFO → MDW, at 57.9%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 89.4% of the time and 9 PM–5 AM departures 49.0%.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Southwest Airlines | 973 | 77.1% | 0.82% | -2 min | 4.4% |
| Frontier Airlines | 274 | 66.5% | 0.36% | -1 min | 14.7% |
Southwest Airlines flew 78.0% of the 1,247 flights listed.
Southwest Airlines arrived on time 10.6 percentage points more often than Frontier Airlines on this route.
Other ways to fly San Francisco to Chicago
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| SFO→ORD San Francisco to Chicago | 16,120 | 78.7% | 1.12% | -7 min | 66 |
| SFO→MDW this route San Francisco to Chicago | 1,247 | 74.8% | 0.72% | -2 min | 67 |
Flying to MDW from the San Francisco area? Compare SFO, SJC, OAK for MDW, with the same test for what counts as a real difference.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Friday the least, a gap of 11.2 percentage points.
Reliability over time
July 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 72.9% against 82.1% in the 12 months before — declining by 9.2 percentage points.
Data and methodology
Calculated by FlyerIntel from 1,247 SFO → MDW flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed