Chicago, IL · departure reliability
MDW
Chicago Midway International
- Departures
- 73,750
- Period
- September 2025 to August 2026
- Carriers
- 4
- US rank
- #29 by volume
Chicago
Chicago Midway International 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 an hour behind schedule. That rests on 73,750 flights, of which Delta Air Lines flew 1,359 at 87.0% on time.
Delta Air Lines is the most reliable of the four carriers covered here at 87.0% on time across 1,359 flights.
Key figures
On time
74.2%
Departures arriving under 15 minutes late at their destination
Avg delay
57 min
Across delayed flights only
Cancelled
1.52%
National rate is 1.89%
Best carrier
Delta
87.0% on time here
These figures cover 74,000 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.
Carrier by carrier
Which airlines run best out of MDW
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 69,564 | 74.0% | 55 min | 1.48% | C |
| Frontier Airlines | 1,670 | 72.4% | 83 min | 2.34% | C |
| Delta Air Lines | 1,359 | 87.0% | 95 min | 2.72% | A |
| SkyWest Airlines | 849 | 80.7% | 87 min | 1.30% | B |
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
Busiest routes out of MDW
Route-level records vary far more than the airport average. These are the 25 busiest departures from MDW, each with its own on-time rate against the airport-wide 74.2%.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| MDW to ATL · Atlanta | 3,538 | 78.7% | 64 min | 2.01% | B |
| MDW to PHX · Phoenix | 2,719 | 74.7% | 57 min | 1.58% | C |
| MDW to MCO · Orlando | 2,707 | 75.2% | 58 min | 1.55% | B |
| MDW to LGA · New York | 2,391 | 68.1% | 59 min | 4.48% | C− |
| MDW to MSP · Minneapolis | 2,275 | 77.0% | 64 min | 1.85% | B |
| MDW to DEN · Denver | 2,259 | 72.9% | 59 min | 1.33% | C |
| MDW to LAS · Las Vegas | 2,236 | 76.1% | 51 min | 0.89% | B+ |
| MDW to DAL · Dallas | 2,204 | 76.1% | 57 min | 1.95% | B |
| 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 | 1,843 | 78.0% | 61 min | 2.71% | B |
| MDW to STL · St. Louis | 1,701 | 80.5% | 58 min | 1.23% | B |
| MDW to TPA · Tampa | 1,569 | 76.4% | 57 min | 1.34% | B |
| MDW to PHL · Philadelphia | 1,513 | 74.9% | 64 min | 1.72% | 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 DTW · Detroit | 1,183 | 75.9% | 55 min | 1.61% | 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 |
Departure window
The best time of day to leave MDW
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 15 points between the best and worst carrier.
- 5am–8am9,122 flights89.7%
- 8am–11am18,368 flights83.4%
- 11am–2pm12,354 flights75.6%
- 2pm–5pm9,828 flights69.4%
- 5pm–8pm13,741 flights63.7%
- 8pm–5am10,337 flights61.0%
Scale runs 55% to 95%.
The 8pm–5am window is where this operation falls apart: 61.0% on time, against 89.7% 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 18,368 flights scheduled in it.
Explore
Filter MDW departures by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On departures from Chicago (MDW), the best departure window is 5am–8am at 89.7% on time and the worst is 8pm–5am at 61.0%, a wide gap of 28.7 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.7%
- 8–11am83.4%
- 11am–2pm75.6%
- 2–5pm69.4%
- 5–8pm63.7%
- 8pm–5am61.0%
best all US flightsScale 55% to 95%.
Across the year
When MDW runs late
MDW's year swings by 20 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 64.2% on time, 20 points below September, the best at 84.1%. 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 7,279 flights.
Across the week, Wednesday is the strongest day at 79.1% on time and Sunday the weakest at 69.3%, a spread of 10 points.
MDW month by month
Delay causes
Why MDW gets delayed
Late-arriving aircraft accounts for 43% of the 1.05 million delay minutes carriers reported here, and the remaining four split what is left.
- 43%Late-arriving aircraft
- 33%Carrier
- 20%National Airspace System
- 4%Extreme weather
- 0%Security
43% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1.05 million reported delay minutes here, that single category outweighs weather by 12 to one. The split is drawn from 1,053,106 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 89.7% on time here.
Cancellations sit at 1.52% against a national 1.89%, which is ordinary. Diversions add another 0.32%.
7.6% 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 an hour, which a normal layover absorbs.
73,750 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.
What to do with this
Flying out of MDW
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 84.1% on time and June 64.2%, a swing of 20 points. If the dates move at all, move them out of June before you think about anything else. 72,395 completed flights over 12 months sit behind that.
Common questions
MDW delay questions
How often is Chicago (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 25.8% of the 73,750 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on Chicago (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 Chicago (MDW)?
The 5am–8am departure window is the strongest at 89.7% on time. The 8pm–5am window is the weakest at 61.0%, 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 June delays on Chicago (MDW)?
June is the weakest month at 64.2% on time, compared with 84.1% 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
- MDW to ATL — Atlanta78.7%
- MDW to PHX — Phoenix74.7%
- MDW to MCO — Orlando75.2%
- MDW to LGA — New York68.1%
- MDW to MSP — Minneapolis77.0%
- MDW to DEN — Denver72.9%
- Southwest Airlines on-time record74.0%
- Frontier Airlines on-time record72.4%
- Delta Air Lines on-time record87.0%
- SkyWest Airlines on-time record80.7%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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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.