Carrier route record
WNDEN→ORD
Southwest Airlines · Denver to Chicago
- Flights
- 482
- Period
- July 2025 to June 2026
- Share of route
- 8%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to ORD draws a D+. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 482 flights. The strongest carrier on the route with a full sample, American Airlines, flew 1,469 at 73.0% on time.
The national on-time rate over the same period is 77.6%, so Southwest on DEN to ORD runs 14 points behind the country as a whole. Across a thousand flights that is about 139 extra late arrivals.
Key figures
On time
63.7%
Arrivals under 15 minutes late, of 476 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.62%
National rate is 1.81%
Whole route
71.1%
Every carrier on DEN to ORD, 6,161 flights
These figures cover 482 flights between July 2025 and June 2026. Beyond the headline rate, 11.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Southwest against every carrier on DEN to ORD
Southwest flew 482 of the 6,161 flights on DEN to ORD, about 8% of it. Its 63.7% on time is 7 points worse than the route as a whole, which runs 71.1%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from Envoy at 74.0% to Southwest at 63.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 125 | 74.0% | 60 min | 0.80% | C+ |
| American Airlines | 1,469 | 73.0% | 124 min | 2.04% | C |
| United Airlines | 3,756 | 71.4% | 79 min | 0.75% | C+ |
| Frontier Airlinesthin sample | 329 | 68.6% | 96 min | 1.22% | C |
| Southwest Airlines (this page) | 482 | 63.7% | 63 min | 0.62% | D+ |
No carrier stands out. American tops the table at 73.0%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 2 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am5 flights—
- 8am–11am169 flights74.6%
- 11am–2pm194 flights55.8%
- 2pm–5pm—
- 5pm–8pm114 flights58.9%
- 8pm–5am—
Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 55.8% on time against 74.6% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 194 flights scheduled in it.
Across the year
Southwest on DEN to ORD through the year
- Jul–Sep 2025267 flights60.3%
- Oct–Dec 2025110 flights74.5%
- Jan–Mar 202641 flights72.5%
- Apr–Jun 202664 flights53.1%
Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 63.7% on time across 482 flights.
Southwest on DEN to ORD did not run the same all year. Its best quarter was Oct–Dec 2025 at 74.5% on time and its weakest Apr–Jun 2026 at 53.1%, a swing of 21 points on roughly 121 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Saturday is the strongest day at 68.2% on time and Sunday the weakest at 49.3%. 19 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
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 11,000 reported delay minutes.
- 36%Late-arriving aircraft
- 31%Carrier
- 30%National Airspace System
- 3%Extreme weather
36% 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 11,000 reported delay minutes here, that single category outweighs weather by 11 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. The split is drawn from 10,950 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 74.6% on time here.
Cancellations are rare at 0.62%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.8% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 888 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 73.0% on time across 483 flights, 9 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 9 points of difference.
One caution: this is a thin sample. 482 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on DEN to ORD
Put together: treat all of this as provisional. 482 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 63.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 476 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to ORD, every carrier
- Southwest on ORD to DEN, the return leg
- Envoy Air on DEN to ORD74.0%
- American Airlines on DEN to ORD73.0%
- United Airlines on DEN to ORD71.4%
- Frontier Airlines on DEN to ORD68.6%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.