Route reliability record
MDW→DEN
Chicago to Denver
- Flights
- 2,259
- Period
- September 2025 to August 2026
- Distance
- 895 mi
- Carriers
- 2
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 2,259 MDW to DEN flights, with a median arrival 2 minutes early.
Best time to fly MDW to DEN: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 91.8% of the time and Tuesday flights 78.8%, against 72.9% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 4 points behind the country as a whole. Across a thousand flights that is about 44 extra late arrivals.
Key figures
On time
72.9%
Arrivals under 15 minutes late, of 2,219 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
1.33%
National rate is 1.89%
Best carrier
Southwest
72.9% on time across 2,203 flights
These figures cover 2,259 flights between September 2025 and August 2026. Beyond the headline rate, 9.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on MDW to DEN
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 2,203 | 72.9% | 59 min | 1.32% | C |
| Frontier Airlinesthin sample | 56 | 70.4% | 66 min | 1.79% | C |
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Best ways to make this trip
The most reliable ways to fly Chicago to Denver
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. ORD → DENChicago to Denver | United Airlines | 77.6% | 78.3% | 0.87% | 5am–8am, Sat | UA 1803 10:40 |
| 2. MDW → DENChicago to Denver | Southwest Airlines | 71.9% | 72.9% | 1.32% | 5am–8am, Tue (route) | — |
| 3. ORD → DENChicago to Denver | American Airlines | 64.5% | 65.5% | 1.56% | 5am–8am, Tue | AA 1387 20:45 |
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 37 points, against half a point between the best and worst carrier.
- 5am–8am320 flights91.8%
- 8am–11am462 flights83.4%
- 11am–2pm377 flights80.1%
- 2pm–5pm425 flights60.2%
- 5pm–8pm376 flights54.7%
- 8pm–5am299 flights67.4%
Scale runs 45% to 95%.
The 5pm–8pm window is where this operation falls apart: 54.7% on time, against 91.8% 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 462 flights scheduled in it.
Explore
Filter MDW to DEN 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 MDW to DEN, the best departure window is 5am–8am at 91.8% on time and the worst is 5pm–8pm at 54.7%, a wide gap of 37.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am91.8%
- 8–11am83.4%
- 11am–2pm80.1%
- 2–5pm60.2%
- 5–8pm54.7%
- 8pm–5am67.4%
best all US flightsScale 45% to 95%.
Across the year
When delays peak on this route
This route's year swings by 27 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 58.1% on time, 27 points below September, the best at 85.1%. 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 235 flights.
Across the week, Tuesday is the strongest day at 78.8% on time and Monday the weakest at 66.6%, a spread of 12 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 36,000 reported delay minutes.
- 40%Late-arriving aircraft
- 29%National Airspace System
- 28%Carrier
- 2%Extreme weather
- 1%Security
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 36,000 reported delay minutes here, that single category outweighs weather by 17 to one. The split is drawn from 35,551 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 91.8% on time here.
Cancellations sit at 1.33% against a national 1.89%, which is ordinary. Diversions add another 0.44%.
Connections and stage length
What a delay here actually costs
9.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
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 74.4% on time across 2,197 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 2,259 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 DEN 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. September runs 85.1% on time and August 58.1%, a swing of 27 points. If the dates move at all, move them out of August before you think about anything else. 2,219 completed flights over 12 months sit behind that.
Common questions
MDW to DEN questions
How often is MDW to DEN 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 27.1% of the 2,259 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is MDW to DEN compared with the rest of the country?
72.9% of flights arrive on time here against a national 77.3%, a difference of 4 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on MDW to DEN?
The 5am–8am departure window is the strongest at 91.8% on time. The 5pm–8pm window is the weakest at 54.7%, 37 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 MDW to DEN?
August is the weakest month at 58.1% on time, compared with 85.1% in September. Across the year that is 27 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
- DEN to MDW — the return legseparate record
- Chicago Midway International (MDW) delay statistics
- Denver International (DEN) delay statistics
- MDW to ATL, a related route78.7%
- PHX to DEN, a related route76.7%
- MDW to PHX, a related route74.7%
- Southwest Airlines on-time record72.9%
- Frontier Airlines on-time record70.4%
- 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. MDW to DEN and DEN to MDW 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.