Route reliability record
ASE→DEN
Aspen to Denver
- Flights
- 2,716
- Period
- July 2025 to June 2026
- Distance
- 125 mi
- Carriers
- 1
This route carries a cancellation problem, not just a delay problem: 5.2% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a B− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 2,716 flights, with a median arrival 7 minutes early.
The US average over the same twelve months is 77.6%, 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
75.2%
Arrivals under 15 minutes late, of 2,573 completed flights
Avg delay
102 min
Across delayed arrivals only, not all flights
Cancelled
5.15%
National rate is 1.81%
Best carrier
SkyWest
75.2% on time across 2,716 flights
These figures cover 2,716 flights between July 2025 and June 2026. Beyond the headline rate, 13.4% 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
Which airline is most reliable on ASE 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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 2,716 | 75.2% | 102 min | 5.15% | B− |
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 23 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am332 flights88.0%
- 8am–11am604 flights80.1%
- 11am–2pm760 flights75.2%
- 2pm–5pm581 flights64.6%
- 5pm–8pm439 flights72.4%
- 8pm–5am—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 88.0% of the time, against 64.6% for the afternoon window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 760 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 33 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 55.3% on time, 33 points below May, the best at 88.0%. 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. March was the busiest month here, with 310 flights.
Across the week, Wednesday is the strongest day at 79.8% on time and Saturday the weakest at 71.7%. 8 points is a smaller lever than departure hour, but it is free.
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 65,000 reported delay minutes.
- 29%Late-arriving aircraft
- 28%National Airspace System
- 23%Extreme weather
- 20%Carrier
Extreme weather accounts for 23% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 3.7 times the usual weather exposure. The split is drawn from 65,051 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 88.0% on time here.
Cancellations run at 5.15%, against 1.81% nationally. That is about one flight in twenty cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 13.4% 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.
At 125 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg runs 74.8% on time across 2,715 flights, within half a point 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 2,716 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 delay figures matter less here than the 5.15% cancellation rate. A late arrival costs you close to two hours; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,573 completed flights over 12 months sit behind that.
Common questions
ASE to DEN questions
How often is ASE to DEN delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.8% of the 2,716 flights in this analysis, against 22.4% nationally. Delayed flights are late by close to two hours on average.
How reliable is ASE to DEN compared with the rest of the country?
75.2% of flights arrive on time here against a national 77.6%, a difference of 2 points against it. That is worth a B− on this site's grading scale.
What time of day has the fewest delays on ASE to DEN?
The 5am–8am departure window is the strongest at 88.0% on time. The 2pm–5pm window is the weakest at 64.6%, 23 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 ASE to DEN?
July is the weakest month at 55.3% on time, compared with 88.0% in May. Across the year that is 33 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 ASE — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on-time record75.2%
- What a cancellation rate actually tells you (and what it hides)
- The best time of day to fly, according to 7.04 million flight records
Direction matters. ASE to DEN and DEN to ASE 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.