Carrier performance at one airport
WN→MDW
Southwest Airlines at Chicago Midway International
- Departures
- 69,564
- Period
- September 2025 to August 2026
- Routes
- 25
- Rank here
- #3 of 4
Southwest Airlines at Chicago sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about 55 minutes behind schedule. That rests on 69,564 flights, of which Delta Air Lines flew 1,359 at 87.0% on time.
Measured against the airport rather than the country, Southwest Airlines runs half a point behind the 74.3% 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
74.0%
68,312 completed departures
Avg delay
55 min
Across delayed flights only
Cancelled
1.48%
At MDW, this carrier only
Rank here
#3
Of 4 carriers clearing the floor at MDW
These figures cover 70,000 flights between September 2025 and August 2026. The median arrival is 2 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 87.0% of the time; Frontier Airlines manages 72.4%. Sample sizes sit next to every figure, because a two-point gap across 1,670 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,359 | 87.0% | 95 min | 2.72% | A |
| SkyWest Airlines | 849 | 80.7% | 87 min | 1.30% | B |
| Southwest Airlines (this page) | 69,564 | 74.0% | 55 min | 1.48% | C |
| Frontier Airlines | 1,670 | 72.4% | 83 min | 2.34% | C |
The spread between Delta and Frontier is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 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 | 2,610 | 74.7% | 53 min | 1.57% | C |
| MDW to MCO · Orlando | 2,515 | 74.8% | 56 min | 1.55% | C |
| MDW to LGA · New York | 2,391 | 68.1% | 59 min | 4.48% | C− |
| MDW to LAS · Las Vegas | 2,234 | 76.2% | 51 min | 0.90% | B+ |
| MDW to DAL · Dallas | 2,204 | 76.1% | 57 min | 1.95% | B |
| MDW to DEN · Denver | 2,203 | 72.9% | 59 min | 1.32% | C |
| MDW to MCI · Kansas City | 2,108 | 78.0% | 52 min | 1.38% | B |
| MDW to DCA · Washington | 2,100 | 68.9% | 57 min | 1.95% | C |
| MDW to BNA · Nashville | 1,873 | 79.2% | 60 min | 1.39% | B |
| MDW to HOU · Houston | 1,849 | 73.3% | 48 min | 1.24% | C |
| MDW to BWI · Baltimore | 1,787 | 77.8% | 61 min | 2.74% | B |
| MDW to STL · St. Louis | 1,701 | 80.5% | 58 min | 1.23% | B |
| MDW to MSP · Minneapolis | 1,563 | 76.2% | 54 min | 1.98% | B |
| MDW to ATL · Atlanta | 1,539 | 75.1% | 57 min | 1.10% | B |
| MDW to TPA · Tampa | 1,534 | 76.2% | 57 min | 1.30% | B |
| MDW to PHL · Philadelphia | 1,457 | 74.7% | 61 min | 1.78% | C |
| MDW to AUS · Austin | 1,374 | 75.9% | 46 min | 0.95% | B+ |
| MDW to BOS · Boston | 1,368 | 65.9% | 64 min | 1.32% | C |
| MDW to OMA · Omaha | 1,316 | 74.4% | 49 min | 1.06% | C |
| MDW to LAX · Los Angeles | 1,296 | 68.3% | 49 min | 0.93% | C+ |
| MDW to CMH · Columbus | 1,235 | 80.9% | 47 min | 1.78% | B |
| MDW to RSW · Fort Myers | 1,166 | 75.3% | 53 min | 1.46% | B |
| MDW to FLL · Fort Lauderdale | 1,119 | 73.6% | 54 min | 1.43% | C |
| MDW to CLE · Cleveland | 1,115 | 79.6% | 60 min | 1.35% | B |
| MDW to SAN · San Diego | 1,110 | 69.2% | 48 min | 1.17% | C |
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 30 points, against 15 points between the best and worst carrier.
- 5am–8am8,212 flights90.6%
- 8am–11am17,550 flights83.3%
- 11am–2pm11,492 flights75.2%
- 2pm–5pm9,263 flights69.0%
- 5pm–8pm12,872 flights63.0%
- 8pm–5am10,175 flights61.0%
Scale runs 55% to 95%.
The 8pm–5am window is where this operation falls apart: 61.0% 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. The 8am–11am window is the busiest, with 17,550 flights scheduled in it.
Across the year
Seasonal pattern
June is the worst month at 63.8% on time, 20 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. July was the busiest month here, with 7,025 flights.
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. Across 975,000 reported delay minutes here, that single category outweighs weather by 14 to one. The split is drawn from 975,447 reported delay minutes.
Cancellations sit at 1.48% against a national 1.89%, which is ordinary. Diversions add another 0.31%.
7.5% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 55 minutes, which a normal layover absorbs.
69,564 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 June 63.8%, a swing of 20 points. If the dates move at all, move them out of June before you think about anything else. 68,312 completed flights over 12 months sit behind that.
Common questions
Southwest Airlines at MDW
How often is Southwest Airlines at MDW delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.0% of the 69,564 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 55 minutes on average.
Which airline is most reliable on Southwest Airlines at MDW?
Delta Air Lines leads at 87.0% on time across 1,359 flights. Frontier Airlines is at the other end on 72.4%, a gap of 15 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 61.0%, 30 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 June delays on Southwest Airlines at MDW?
June is the weakest month at 63.8% on time, compared with 83.8% in September. Across the year that is 20 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.