Route reliability record
DEN→MDW
Denver to Chicago
- Flights
- 2,197
- Period
- September 2025 to August 2026
- Distance
- 895 mi
- Carriers
- 2
This route 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 2,197 DEN to MDW flights, with a median arrival 2 minutes early.
Best time to fly DEN to MDW: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 93.9% of the time and Wednesday flights 79.8%, against 74.4% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.4%
Arrivals under 15 minutes late, of 2,143 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
1.64%
National rate is 1.89%
Best carrier
Southwest
74.1% on time across 2,140 flights
These figures cover 2,197 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.
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Carrier by carrier
Which airline is most reliable on DEN to MDW
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 57 | 83.9% | 88 min | 1.75% | B |
| Southwest Airlines | 2,140 | 74.1% | 56 min | 1.64% | C |
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Best ways to make this trip
The most reliable ways to fly Denver to Chicago
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 2 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → MDWDenver to Chicago | Southwest Airlines | 72.9% | 74.1% | 1.64% | 5am–8am, Wed (route) | — |
| 2. DEN → ORDDenver to Chicago | American Airlines | 72.0% | 73.3% | 1.83% | 5am–8am, Sat | AA 2771 07:16 |
| 3. DEN → ORDDenver to Chicago | United Airlines | 71.3% | 71.9% | 0.82% | 5am–8am, Tue | UA 1377 06:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 45 points, against half a point between the best and worst carrier.
- 5am–8am392 flights93.9%
- 8am–11am412 flights88.8%
- 11am–2pm425 flights79.7%
- 2pm–5pm337 flights71.4%
- 5pm–8pm434 flights51.4%
- 8pm–5am197 flights49.2%
Scale runs 40% to 100%.
The 8pm–5am window is where this operation falls apart: 49.2% on time, against 93.9% 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 5pm–8pm window is the busiest, with 434 flights scheduled in it.
Explore
Filter DEN to MDW 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 DEN to MDW, the best departure window is 5am–8am at 93.9% on time and the worst is 8pm–5am at 49.2%, a wide gap of 44.7 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.9%
- 8–11am88.8%
- 11am–2pm79.7%
- 2–5pm71.4%
- 5–8pm51.4%
- 8pm–5am49.2%
best all US flightsScale 40% to 100%.
Across the year
When delays peak on this route
This route's year swings by 25 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.
August is the worst month at 60.5% on time, 25 points below January, the best at 85.9%. 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. October was the busiest month here, with 214 flights.
Across the week, Wednesday is the strongest day at 79.8% on time and Thursday the weakest at 68.6%, a spread of 11 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 49% of the 31,000 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Late-arriving aircraft
- 34%Carrier
- 15%National Airspace System
- 2%Extreme weather
- 0%Security
49% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 31,000 reported delay minutes here, that single category outweighs weather by 25 to one. The split is drawn from 30,911 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 93.9% on time here.
Cancellations sit at 1.64% against a national 1.89%, which is ordinary. Diversions add another 0.82%.
Connections and stage length
What a delay here actually costs
7.9% 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.
The 895 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg runs 72.9% on time across 2,259 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,197 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in MDW after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 85.9% on time and August 60.5%, a swing of 25 points. If the dates move at all, move them out of August before you think about anything else. 2,143 completed flights over 12 months sit behind that.
Common questions
DEN to MDW questions
How often is DEN to 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 25.6% of the 2,197 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is DEN to MDW compared with the rest of the country?
74.4% of flights arrive on time here against a national 77.3%, a difference of 3 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on DEN to MDW?
The 5am–8am departure window is the strongest at 93.9% on time. The 8pm–5am window is the weakest at 49.2%, 45 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 August delays on DEN to MDW?
August is the weakest month at 60.5% on time, compared with 85.9% in January. Across the year that is 25 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 DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Chicago Midway International (MDW) delay statistics
- DEN to PHX, a related route75.6%
- ATL to MDW, a related route75.2%
- DEN to SLC, a related route78.2%
- Frontier Airlines on-time record83.9%
- Southwest Airlines on-time record74.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. DEN to MDW and MDW to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.