Route reliability record
DEN→DSM
Denver to Des Moines
- Flights
- 2,329
- Period
- July 2025 to June 2026
- Distance
- 589 mi
- Carriers
- 4
This route lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 2,329 flights, of which SkyWest Airlines flew 936 at 88.2% on time.
SkyWest Airlines is the most reliable of the three carriers covered here at 88.2% on time across 936 flights.
Key figures
On time
79.9%
Arrivals under 15 minutes late, of 2,310 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.56%
National rate is 1.81%
Best carrier
SkyWest
88.2% on time across 936 flights
These figures cover 2,329 flights between July 2025 and June 2026. The median arrival is 7 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 airline is most reliable on DEN to DSM
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 88.2% of the time; Southwest Airlines manages 67.2%. Sample sizes sit next to every figure, because a two-point gap across 559 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 | 559 | 67.2% | 64 min | 0.36% | C+ |
The spread between SkyWest and Southwest is 21 points, wide enough that it should decide the booking. On a hundred trips that is 21 more arrivals inside the on-time window.
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 29 points, against 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am81 flights95.1%
- 8am–11am606 flights89.1%
- 11am–2pm494 flights87.0%
- 2pm–5pm91 flights74.7%
- 5pm–8pm626 flights65.8%
- 8pm–5am431 flights77.6%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.1% of the time, against 65.8% for the evening window. That is 29 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 626 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 21 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.
July is the worst month at 67.7% on time, 21 points below October, the best at 88.4%. 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. August was the busiest month here, with 227 flights.
Across the week, Wednesday is the strongest day at 85.6% on time and Friday the weakest at 76.9%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 32,000 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.
- 50%Late-arriving aircraft
- 36%Carrier
- 11%National Airspace System
- 3%Extreme weather
- 0%Security
50% 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 32,000 reported delay minutes here, that single category outweighs weather by 16 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 31,713 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 11,000 of the 32,000 delay minutes reported here.
Cancellations are rare at 0.56%, 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 actually costs
7.4% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the a little over an hour kind, which a normal layover absorbs.
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 83.0% on time across 2,329 flights, 3 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 3 points of difference.
The sample behind these figures is 2,329 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.
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 88.4% on time and July 67.7%, a swing of 21 points. If the dates move at all, move them out of July before you think about anything else. 2,310 completed flights over 12 months sit behind that.
Common questions
DEN to DSM questions
How often is DEN to DSM delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.1% of the 2,329 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on DEN to DSM?
SkyWest Airlines leads at 88.2% on time across 936 flights. Southwest Airlines is at the other end on 67.2%, a gap of 21 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 DEN to DSM?
The 5am–8am departure window is the strongest at 95.1% on time. The 5pm–8pm window is the weakest at 65.8%, 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 July delays on DEN to DSM?
July is the weakest month at 67.7% on time, compared with 88.4% in October. Across the year that is 21 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
- DSM to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on-time record88.2%
- Frontier Airlines on-time record79.7%
- United Airlines on-time record79.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. DEN to DSM and DSM to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.