Route profile
MDW→SAN
Flight reliability, delays and best times to fly from Chicago to San Diego, 1,728 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 49% of comparable major US routes (4,598 compared)
Calculated from 3,284 flights. How this is calculated · What counts as on time
MDW → SAN arrives on time 74.7% of the time; the return trip, SAN → MDW, arrives on time 77.6% of the time, a 2.9-point gap between the two directions of the same city pair.
MDW → SAN spends 19.5 minutes on the ground on a 1,728-mile trip: 14.9 minutes from pushback to wheels-up at MDW and 4.6 minutes from touchdown to gate at SAN.
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.
88.0% on time for 5–9 AM departures, against 50.3% 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 MDW to SAN differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
MDW to SAN struggles most at 9 PM: 50.3% of its flights scheduled then arrive on time, 17.8 points behind the 68.1% on routes of similar length at the same hour. Against all other routes the gap is 19.2 points.
MDW to SAN is at its best against routes of similar length for flights scheduled at 7 PM: 78.2% arrive on time, 12.5 points ahead of the 65.7% those routes manage at that hour. Against all other routes the gap is 10.4 points.
Tuesday is the day MDW to SAN slips furthest against routes of similar length, 75.7% on time where they average 80.9%, 5.2 points lower. Against all other routes the gap is 5.9 points.
In June, MDW to SAN runs 11.9 points below routes of similar length, 60.5% on time to 72.4%. Against all other routes the gap is 12.2 points.
MDW to SAN against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 9 PM departures | 50.3% | routes of similar length | 68.1% | −17.8 pts | 165 here, 31,208 there |
| Hour: 7 PM departures | 78.2% | routes of similar length | 65.7% | +12.5 pts | 156 here, 52,563 there |
| Weekday: Tuesday | 75.7% | routes of similar length | 80.9% | −5.2 pts | 441 here, 189,360 there |
| Month: June | 60.5% | routes of similar length | 72.4% | −11.9 pts | 286 here, 123,094 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 1,728 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
42 min late
against a median of 1 min early
Percentiles over 3,284 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SAN after arriving from MDW.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 47% | Likely to miss |
| 45 min | 24% | High risk |
| 60 min | 15% | Some risk |
| 90 min | 5.6% | Some risk |
| 120 min | 2.6% | 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 1.16% of the time and diverts 0.61% of the time, which a late arrival never shows up in.
Chance of missing is the share of 3,226 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 42 minutes late (90th-percentile gate arrival delay), over 3,284 operations.
Any other layover length: connection checker.
Best time to fly
MDW → SAN flights departing 5–9 AM arrived on time 88.0% of the time, against 50.3% for 9 PM–5 AM departures, a gap of 37.7 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 90.8% on time from 169 flights
- 6 AM: 91.8% on time from 335 flights
- 7 AM: 88.1% on time from 186 flights
- 8 AM: 83.5% on time from 382 flights
- 9 AM: too few flights to score
- 10 AM: 67.4% on time from 238 flights
- 11 AM: 77.2% on time from 205 flights
- 12 PM: 74.5% on time from 199 flights
- 1 PM: 79.4% on time from 141 flights
- 2 PM: 58.9% on time from 143 flights
- 3 PM: 69.4% on time from 126 flights
- 4 PM to 6 PM: too few flights to score
- 7 PM: 78.2% on time from 160 flights
- 8 PM: 64.6% on time from 495 flights
- 9 PM: 50.3% on time from 175 flights
- 10 PM to 11 PM: too few flights to score
Why MDW → SAN 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
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for MDW → SAN. Only delays of 15 minutes or more are attributed. What the five causes mean
Late-arriving aircraft is the largest cause on MDW → SAN, at 38.4%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 88.0% of the time and 9 PM–5 AM departures 50.3%.
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 | 3,284 | 74.7% | 1.16% | -1 min | 5.8% |
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Sunday the least, a gap of 7.8 percentage points.
By month
- Jan: 82.3%
- Feb: 80.3%
- Mar: 76.1%
- Apr: 72.0%
- May: 70.6%
- Jun: 60.5%
- Jul: 67.6%
- Aug: 75.7%
- Sep: 76.3%
- Oct: 80.8%
- Nov: 84.0%
- Dec: 79.3%
June is historically the weakest month and November the strongest, a spread of 23.5 percentage points.
Reliability over time
July 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 72.2% against 79.5% in the 12 months before — declining by 7.3 percentage points.
Data and methodology
Calculated by FlyerIntel from 3,284 MDW → SAN 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