Route reliability record
COS→DEN
Colorado Springs to Denver
- Flights
- 4,989
- Period
- September 2025 to August 2026
- Distance
- 73 mi
- Carriers
- 3
This route lands a B, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 4,989 COS to DEN flights, of which SkyWest Airlines flew 3,337 at 83.4% on time.
Best time to fly COS to DEN: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 91.2% of the time and Saturday flights 82.9%, against 81.4% for the route overall.
SkyWest Airlines is the most reliable of the three carriers covered here at 83.4% on time across 3,337 flights.
Key figures
On time
81.4%
Arrivals under 15 minutes late, of 4,929 completed flights
Avg delay
72 min
Across delayed arrivals only, not all flights
Cancelled
1.14%
National rate is 1.89%
Best carrier
SkyWest
83.4% on time across 3,337 flights
These figures cover 4,989 flights between September 2025 and August 2026. The median arrival is 10 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Which airline is most reliable on COS to DEN
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 83.4% of the time; United Airlines manages 76.3%. Sample sizes sit next to every figure, because a two-point gap across 527 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 3,337 | 83.4% | 77 min | 1.53% | B |
| Southwest Airlines | 1,125 | 77.8% | 60 min | 0.27% | B+ |
| United Airlines | 527 | 76.3% | 73 min | 0.57% | B+ |
SkyWest leads United by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on COS to DEN
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Best ways to make this trip
The most reliable ways to fly Colorado Springs to Denver
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. COS → DENColorado Springs to Denver | SkyWest Airlines | 82.1% | 83.4% | 1.53% | 5am–8am, Wed | OO 5291 06:00 |
| 2. COS → DENColorado Springs to Denver | Southwest Airlines | 77.6% | 77.8% | 0.27% | 5am–8am, Sat | — |
| 3. COS → DENColorado Springs to Denver | United Airlines | 75.9% | 76.3% | 0.57% | 5am–8am, Sun | — |
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 28 points, against 7 points between the best and worst carrier.
- 5am–8am1,479 flights91.2%
- 8am–11am1,065 flights85.7%
- 11am–2pm1,031 flights82.7%
- 2pm–5pm646 flights70.2%
- 5pm–8pm753 flights63.1%
- 8pm–5am15 flights—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 63.1% on time, against 91.2% 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 5am–8am window is the busiest, with 1,479 flights scheduled in it.
Explore
Filter COS 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 COS to DEN, the best departure window is 5am–8am at 91.2% on time and the worst is 5pm–8pm at 63.1%, a wide gap of 28.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am91.2%
- 8–11am85.7%
- 11am–2pm82.7%
- 2–5pm70.2%
- 5–8pm63.1%
- 8pm–5am—
best all US flightsScale 55% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 4,989 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
August is the worst month at 75.8% on time, 10 points below November, the best at 86.2%. 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. October was the busiest month here, with 450 flights.
Across the week, Saturday is the strongest day at 82.9% on time and Friday the weakest at 78.7%, a spread of 4 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 66,000 reported delay minutes.
- 33%Carrier
- 31%National Airspace System
- 27%Late-arriving aircraft
- 9%Extreme weather
No single cause dominates. carrier at 33%, national airspace system at 31% and late-arriving aircraft at 27% split the 66,000 reported delay minutes between them. An even spread like this usually means the operation is running close to its designed capacity with no one obvious weak point, and it is the hardest pattern for a traveller to route around. The split is drawn from 65,904 reported delay minutes.
Cancellations sit at 1.14% against a national 1.89%, which is ordinary. Diversions add another 0.06%.
Connections and stage length
What a delay here actually costs
7.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
At 73 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 is a different operation and performs like one: it runs 76.5% on time across 4,989 flights, 5 points below 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 5 points of difference.
The sample behind these figures is 4,989 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: avoid the 5pm–8pm departure. It runs 63.1% on time against 91.2% for the 5am–8am slot, and that 28 points is the largest single thing you control here. SkyWest Airlines is the strongest operator if the fares are close. 4,929 completed flights over 12 months sit behind that.
Common questions
COS to DEN questions
How often is COS to DEN delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.6% of the 4,989 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on COS to DEN?
SkyWest Airlines leads at 83.4% on time across 3,337 flights. United Airlines is at the other end on 76.3%, a gap of 7 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 COS to DEN?
The 5am–8am departure window is the strongest at 91.2% on time. The 5pm–8pm window is the weakest at 63.1%, 28 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 COS to DEN?
August is the weakest month at 75.8% on time, compared with 86.2% in November. Across the year that is 10 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 COS — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on COS to DEN83.4%
- Southwest Airlines on COS to DEN77.8%
- United Airlines on COS to DEN76.3%
- COS to DFW, a related route77.9%
- PHX to DEN, a related route76.7%
- COS to PHX, a related route81.3%
- SkyWest Airlines on-time record83.4%
- Southwest Airlines on-time record77.8%
- United Airlines on-time record76.3%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. COS to DEN and DEN to COS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed COS to DEN’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.