Carrier performance at one airport
WN→MDW
Southwest Airlines at Chicago Midway International
- Departures
- 69,280
- Period
- June 2025 to May 2026
- Routes
- 25
- Rank here
- #3 of 4
Southwest Airlines at Chicago sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.4%. The late ones land about an hour behind schedule. That rests on 69,280 flights, of which Delta Air Lines flew 1,406 at 86.1% on time.
Measured against the airport rather than the country, Southwest Airlines runs half a point behind the 75.6% weighted average across all carriers at MDW. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
75.4%
68,157 completed departures
Avg delay
55 min
Across delayed flights only
Cancelled
1.38%
At MDW, this carrier only
Rank here
#3
Of 4 carriers clearing the floor at MDW
These figures cover 69,000 flights between June 2025 and May 2026. The median arrival is 3 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Against the competition
Every carrier at MDW, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.1% of the time; Frontier Airlines manages 73.3%. Sample sizes sit next to every figure, because a two-point gap across 1,903 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,406 | 86.1% | 94 min | 2.99% | A |
| SkyWest Airlines | 1,308 | 79.2% | 80 min | 0.99% | B+ |
| Southwest Airlines (this page) | 69,280 | 75.4% | 55 min | 1.38% | B |
| Frontier Airlines | 1,903 | 73.3% | 80 min | 1.73% | C |
The spread between Delta and Frontier is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.
Route by route
Where Southwest Airlines flies from MDW
Southwest Airlines operates 25 routes out of MDW with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| MDW to PHX · Phoenix | 2,684 | 76.2% | 54 min | 1.56% | B |
| MDW to MCO · Orlando | 2,534 | 76.4% | 56 min | 1.38% | B |
| MDW to LAS · Las Vegas | 2,388 | 76.8% | 52 min | 0.92% | B+ |
| MDW to LGA · New York | 2,368 | 68.9% | 59 min | 3.93% | C− |
| MDW to DEN · Denver | 2,279 | 72.9% | 61 min | 1.18% | C |
| MDW to DAL · Dallas | 2,155 | 77.3% | 58 min | 1.86% | B |
| MDW to DCA · Washington | 2,104 | 69.5% | 59 min | 2.14% | C |
| MDW to MCI · Kansas City | 2,093 | 79.4% | 56 min | 1.29% | B |
| MDW to BNA · Nashville | 1,905 | 80.3% | 60 min | 1.26% | B |
| MDW to HOU · Houston | 1,843 | 74.3% | 46 min | 1.19% | C |
| MDW to BWI · Baltimore | 1,759 | 78.8% | 59 min | 2.73% | B |
| MDW to STL · St. Louis | 1,705 | 82.2% | 58 min | 0.94% | B+ |
| MDW to MSP · Minneapolis | 1,617 | 77.5% | 58 min | 1.61% | B |
| MDW to TPA · Tampa | 1,568 | 76.2% | 56 min | 1.40% | B |
| MDW to ATL · Atlanta | 1,553 | 77.7% | 59 min | 1.22% | B |
| MDW to PHL · Philadelphia | 1,445 | 74.5% | 57 min | 1.25% | C |
| MDW to BOS · Boston | 1,395 | 67.7% | 61 min | 1.08% | C |
| MDW to OMA · Omaha | 1,383 | 76.9% | 53 min | 1.08% | B |
| MDW to LAX · Los Angeles | 1,355 | 70.3% | 49 min | 1.03% | C |
| MDW to AUS · Austin | 1,351 | 76.5% | 48 min | 0.74% | B+ |
| MDW to CMH · Columbus | 1,259 | 79.8% | 59 min | 1.35% | B |
| MDW to RSW · Fort Myers | 1,162 | 75.5% | 51 min | 1.12% | B |
| MDW to PIT · Pittsburgh | 1,148 | 79.9% | 59 min | 1.13% | B |
| MDW to FLL · Fort Lauderdale | 1,133 | 74.8% | 56 min | 1.59% | C |
| MDW to CLE · Cleveland | 1,107 | 78.9% | 54 min | 1.08% | B |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am8,231 flights90.6%
- 8am–11am17,095 flights84.8%
- 11am–2pm11,335 flights77.4%
- 2pm–5pm9,798 flights70.7%
- 5pm–8pm12,013 flights66.2%
- 8pm–5am10,808 flights61.4%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 61.4% on time, against 90.6% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in.
Across the year
Seasonal pattern
July is the worst month at 67.1% on time, 17 points below September, the best at 83.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck.
Delay causes
What holds this operation up
- 44%Late-arriving aircraft
- 32%Carrier
- 20%National Airspace System
- 3%Extreme weather
- 0%Security
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 922,000 reported delay minutes here, that single category outweighs weather by 17 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit.
Cancellations sit at 1.38% against a national 1.80%, which is ordinary. Diversions add another 0.24%.
7.0% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the about an hour kind, which a normal layover absorbs.
69,280 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 83.8% on time and July 67.1%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else.
Common questions
Southwest Airlines at MDW
How often is Southwest Airlines at MDW delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.6% of the 69,280 flights in this analysis, against 22.6% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on Southwest Airlines at MDW?
Delta Air Lines leads at 86.1% on time across 1,406 flights. Frontier Airlines is at the other end on 73.3%, a gap of 13 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Southwest Airlines at MDW?
The 5am–8am departure window is the strongest at 90.6% on time. The 8pm–5am window is the weakest at 61.4%, 29 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on Southwest Airlines at MDW?
July is the weakest month at 67.1% on time, compared with 83.8% in September. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.