Carrier route record
WNDEN→DSM
Southwest Airlines · Denver to Des Moines
- Flights
- 559
- Period
- July 2025 to June 2026
- Share of route
- 24%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to DSM draws a C+. About 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 559 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 936 at 88.2% on time.
The national on-time rate over the same period is 77.6%, so Southwest on DEN to DSM runs 10 points behind the country as a whole. Across a thousand flights that is about 104 extra late arrivals.
Key figures
On time
67.2%
Arrivals under 15 minutes late, of 555 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.36%
National rate is 1.81%
Whole route
79.9%
Every carrier on DEN to DSM, 2,329 flights
These figures cover 559 flights between July 2025 and June 2026. Beyond the headline rate, 11.0% 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 DSM
Southwest flew 559 of the 2,329 flights on DEN to DSM, about 24% of it. Its 67.2% on time is 13 points worse than the route as a whole, which runs 79.9%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from SkyWest at 88.2% to Southwest at 67.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 88.2% of the time; United Airlines manages 79.1%. Sample sizes sit next to every figure, because a two-point gap across 681 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 936 | 88.2% | 71 min | 1.07% | A |
| Frontier Airlinesthin sample | 153 | 79.7% | 58 min | 0.00% | B+ |
| United Airlines | 681 | 79.1% | 74 min | 0.15% | B+ |
| Southwest Airlines (this page) | 559 | 67.2% | 64 min | 0.36% | C+ |
SkyWest leads United by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 38 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am134 flights82.8%
- 11am–2pm75 flights84.0%
- 2pm–5pm31 flights87.1%
- 5pm–8pm251 flights56.0%
- 8pm–5am68 flights49.2%
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 49.2% on time, against 87.1% for the 2pm–5pm 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 251 flights scheduled in it.
Across the year
Southwest on DEN to DSM through the year
June is the worst month at 56.7% on time, 24 points below January, the best at 80.6%. 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 62 flights.
Across the week, Wednesday is the strongest day at 78.0% on time and Monday the weakest at 58.0%. 20 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 62% of the 12,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 62%Late-arriving aircraft
- 31%Carrier
- 7%National Airspace System
- 0%Security
62% 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 12,000 reported delay minutes here, that single category outweighs weather by 62 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 11,655 reported delay minutes.
Cancellations are rare at 0.36%, 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. 11.0% 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 589 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 83.4% on time across 559 flights, 16 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 16 points of difference.
One caution: this is a thin sample. 559 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 DSM
Put together: treat all of this as provisional. 559 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 67.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 555 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to DSM, every carrier
- Southwest on DSM to DEN, the return leg
- SkyWest Airlines on DEN to DSM88.2%
- Frontier Airlines on DEN to DSM79.7%
- United Airlines on DEN to DSM79.1%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.