Carrier route record
WNCOS→DEN
Southwest Airlines · Colorado Springs to Denver
- Flights
- 1,142
- Period
- July 2025 to June 2026
- Share of route
- 23%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on COS to DEN sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,142 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 3,282 at 81.3% on time.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on COS to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 1,137 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.35%
National rate is 1.81%
Whole route
78.8%
Every carrier on COS to DEN, 5,038 flights
These figures cover 1,142 flights between July 2025 and June 2026. The median arrival is 6 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
Southwest against every carrier on COS to DEN
Southwest flew 1,142 of the 5,038 flights on COS to DEN, about 23% of it. Its 75.0% on time is 4 points worse than the route as a whole, which runs 78.8%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from SkyWest at 81.3% to United at 72.9%.
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 81.3% of the time; United Airlines manages 72.9%. Sample sizes sit next to every figure, because a two-point gap across 614 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 3,282 | 81.3% | 75 min | 1.68% | B |
| Southwest Airlines (this page) | 1,142 | 75.0% | 57 min | 0.35% | B+ |
| United Airlines | 614 | 72.9% | 81 min | 1.30% | C |
SkyWest leads United by 8 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 42 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am365 flights89.9%
- 8am–11am124 flights88.7%
- 11am–2pm240 flights77.5%
- 2pm–5pm168 flights68.3%
- 5pm–8pm245 flights47.7%
- 8pm–5am—
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 47.7% on time, against 89.9% 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 365 flights scheduled in it.
Across the year
Southwest on COS to DEN through the year
July is the worst month at 56.2% on time, 36 points below January, the best at 91.8%. 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. May was the busiest month here, with 103 flights.
Across the week, Saturday is the strongest day at 81.2% on time and Friday the weakest at 67.1%. 14 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. National Airspace System accounts for 49% of the 16,000 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.
- 49%National Airspace System
- 36%Late-arriving aircraft
- 13%Carrier
- 1%Extreme weather
36% 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 16,000 reported delay minutes here, that single category outweighs weather by 30 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 16,086 reported delay minutes.
49% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 7,901 minutes out of 16,000, against a national NAS share of 21%.
Cancellations are rare at 0.35%, 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
7.7% 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 last about 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 runs 72.9% on time across 1,142 flights, within 2 points 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 1,142 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 Southwest on COS to DEN
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 91.8% on time and July 56.2%, a swing of 36 points. If the dates move at all, move them out of July before you think about anything else. 1,137 completed flights over 12 months sit behind that.
Related
Where to go next
- COS to DEN, every carrier
- Southwest on DEN to COS, the return leg
- SkyWest Airlines on COS to DEN81.3%
- United Airlines on COS to DEN72.9%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.