Route reliability record
DEN→COS
Denver to Colorado Springs
- Flights
- 4,989
- Period
- September 2025 to August 2026
- Distance
- 73 mi
- Carriers
- 3
This route lands a B, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 4,989 DEN to COS flights, of which United Airlines flew 526 at 81.1% on time.
Best time to fly DEN to COS: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 87.1% of the time and Tuesday flights 80.2%, against 76.5% for the route overall.
United Airlines is the most reliable of the three carriers covered here at 81.1% on time across 526 flights.
Key figures
On time
76.5%
Arrivals under 15 minutes late, of 4,924 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
1.26%
National rate is 1.89%
Best carrier
United
81.1% on time across 526 flights
These figures cover 4,989 flights between September 2025 and August 2026. Beyond the headline rate, 9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on DEN to COS
The choice of carrier is not cosmetic here. United Airlines arrives on time 81.1% of the time; Southwest Airlines manages 74.0%. Sample sizes sit next to every figure, because a two-point gap across 1,125 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 526 | 81.1% | 67 min | 0.57% | B+ |
| SkyWest Airlines | 3,338 | 76.6% | 73 min | 1.65% | B |
| Southwest Airlines | 1,125 | 74.0% | 55 min | 0.44% | C+ |
United leads Southwest by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on DEN to COS
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.
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Best ways to make this trip
The most reliable ways to fly Denver to Colorado Springs
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. DEN → COSDenver to Colorado Springs | United Airlines | 80.6% | 81.1% | 0.57% | 2pm–5pm, Wed | — |
| 2. DEN → COSDenver to Colorado Springs | SkyWest Airlines | 75.3% | 76.6% | 1.65% | 5am–8am, Tue | OO 5246 07:45 |
| 3. DEN → COSDenver to Colorado Springs | Southwest Airlines | 73.7% | 74.0% | 0.44% | 8am–11am, Tue | — |
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 22 points, against 7 points between the best and worst carrier.
- 5am–8am217 flights83.9%
- 8am–11am794 flights87.1%
- 11am–2pm939 flights81.1%
- 2pm–5pm830 flights78.9%
- 5pm–8pm974 flights65.6%
- 8pm–5am1,235 flights71.8%
Scale runs 55% to 95%.
Book the morning departure. Flights leaving between 8am–11am arrive on time 87.1% of the time, against 65.6% for the evening window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 1,235 flights scheduled in it.
Explore
Filter DEN to COS 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 DEN to COS, the best departure window is 8am–11am at 87.1% on time and the worst is 5pm–8pm at 65.6%, a wide gap of 21.5 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am83.9%
- 8–11am87.1%
- 11am–2pm81.1%
- 2–5pm78.9%
- 5–8pm65.6%
- 8pm–5am71.8%
best all US flightsScale 55% to 95%.
Across the year
When delays peak on this route
This route's year swings by 24 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.
August is the worst month at 62.7% on time, 24 points below November, the best at 86.5%. 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, Tuesday is the strongest day at 80.2% on time and Friday the weakest at 74.1%, a spread of 6 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 79,000 reported delay minutes.
- 38%Carrier
- 37%Late-arriving aircraft
- 17%National Airspace System
- 8%Extreme weather
- 0%Security
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 79,000 reported delay minutes here, that single category outweighs weather by 5 to one. The split is drawn from 78,803 reported delay minutes.
The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 30,000 of the 79,000 delay minutes reported here.
Cancellations sit at 1.26% against a national 1.89%, which is ordinary. Diversions add another 0.04%.
Connections and stage length
What a delay here actually costs
9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
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 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 81.4% on time across 4,989 flights, 5 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 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 COS after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 86.5% on time and August 62.7%, a swing of 24 points. If the dates move at all, move them out of August before you think about anything else. 4,924 completed flights over 12 months sit behind that.
Common questions
DEN to COS questions
How often is DEN to COS delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.5% 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 DEN to COS?
United Airlines leads at 81.1% on time across 526 flights. Southwest Airlines is at the other end on 74.0%, 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 DEN to COS?
The 8am–11am departure window is the strongest at 87.1% on time. The 5pm–8pm window is the weakest at 65.6%, 22 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 DEN to COS?
August is the weakest month at 62.7% on time, compared with 86.5% in November. Across the year that is 24 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
- COS to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- United Airlines on DEN to COS81.1%
- SkyWest Airlines on DEN to COS76.6%
- Southwest Airlines on DEN to COS74.0%
- DEN to PHX, a related route75.6%
- DFW to COS, a related route72.5%
- DEN to SLC, a related route78.2%
- United Airlines on-time record81.1%
- SkyWest Airlines on-time record76.6%
- Southwest Airlines on-time record74.0%
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
Direction matters. DEN to COS and COS to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.