Carrier route record

WNDEN→COS

Southwest Airlines · Denver to Colorado Springs

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 DEN to COS sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land roughly 55 minutes behind schedule. That rests on 1,142 flights. The strongest carrier on the route with a full sample, United Airlines, flew 614 at 77.3% on time.

The national on-time rate over the same period is 77.6%, so Southwest on DEN to COS runs 5 points behind the country as a whole. Across a thousand flights that is about 47 extra late arrivals.

On time

72.9%

Arrivals under 15 minutes late, of 1,137 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.44%

National rate is 1.81%

Whole route

75.8%

Every carrier on DEN to COS, 5,039 flights

These figures cover 1,142 flights between July 2025 and June 2026. The median arrival is 3 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 DEN to COS

Southwest flew 1,142 of the 5,039 flights on DEN to COS, about 23% of it. Its 72.9% on time is 3 points worse than the route as a whole, which runs 75.8%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 77.3% to Southwest at 72.9%.

The two carriers here are closely matched: about a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on DEN to COS
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	614	77.3%	69 min	0.98%	B+
SkyWest Airlines	3,283	76.5%	72 min	1.89%	B
Southwest Airlines (this page)	1,142	72.9%	54 min	0.44%	C+

No carrier stands out. United tops the table at 77.3%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.

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 34 points, against about a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am5 flights—
8am–11am308 flights90.6%
11am–2pm109 flights79.8%
2pm–5pm285 flights71.2%
5pm–8pm82 flights56.2%
8pm–5am353 flights60.6%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 56.2% on time, against 90.6% for the 8am–11am 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 8pm–5am window is the busiest, with 353 flights scheduled in it.

Across the year

Southwest on DEN to COS through the year

Darker means more delays. Figures are on-time percentages.April best, July worst

July is the worst month at 51.0% on time, 37 points below April, the best at 87.6%. 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, Tuesday is the strongest day at 76.5% on time and Thursday the weakest at 69.2%. 7 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. Late-arriving aircraft accounts for 56% of the 17,000 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.

Late-arriving aircraft
56%
Carrier
31%
National Airspace System
9%
Extreme weather
3%
Security
1%

56% 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 17,000 reported delay minutes here, that single category outweighs weather by 17 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 16,615 reported delay minutes.

The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 90.6% on time here.

Cancellations are rare at 0.44%, 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

7.9% 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 roughly 55 minutes, 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 8am–11am window matters as much as it does.

The return leg runs 75.0% 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 DEN to COS

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 87.6% on time and July 51.0%, a swing of 37 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.

Where to go next

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.

Key figures