Carrier route record

WNMCI→DEN

Southwest Airlines · Kansas City to Denver

Flights: 2,341
Period: July 2025 to June 2026
Share of route: 55%
Carriers: 4

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.

Southwest on MCI to DEN sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 2,341 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 374 at 89.5% on time.

The national on-time rate over the same period is 77.6%, so Southwest on MCI to DEN runs 5 points behind the country as a whole. Across a thousand flights that is about 46 extra late arrivals.

On time

73.0%

Arrivals under 15 minutes late, of 2,316 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.73%

National rate is 1.81%

Whole route

76.1%

Every carrier on MCI to DEN, 4,274 flights

These figures cover 2,341 flights between July 2025 and June 2026. Beyond the headline rate, 8.3% 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

Southwest against every carrier on MCI to DEN

Southwest flew 2,341 of the 4,274 flights on MCI to DEN, most of the route. Its 73.0% on time is 3 points worse than the route as a whole, which runs 76.1%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from SkyWest at 89.5% to Southwest at 73.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 89.5% of the time; United Airlines manages 77.8%. Sample sizes sit next to every figure, because a two-point gap across 1,298 flights means less than a ten-point one.

On-time performance by carrier on MCI to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	374	89.5%	104 min	0.27%	A+
United Airlines	1,298	77.8%	61 min	0.54%	B+
Frontier Airlinesthin sample	261	75.8%	119 min	0.38%	B+
Southwest Airlines (this page)	2,341	73.0%	58 min	0.73%	C+

SkyWest leads United by 12 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 35 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am385 flights91.9%
8am–11am439 flights83.3%
11am–2pm475 flights79.0%
2pm–5pm422 flights59.2%
5pm–8pm484 flights57.4%
8pm–5am136 flights61.7%

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

The 5pm–8pm window is where this operation falls apart: 57.4% on time, against 91.9% 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 5pm–8pm window is the busiest, with 484 flights scheduled in it.

Across the year

Southwest on MCI to DEN through the year

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

July is the worst month at 57.7% on time, 29 points below January, the best at 87.0%. 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. June was the busiest month here, with 223 flights.

Across the week, Saturday is the strongest day at 79.9% on time and Sunday the weakest at 69.2%. 11 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 42% of the 37,000 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
42%
National Airspace System
37%
Carrier
16%
Extreme weather
4%
Security
0%

42% 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 37,000 reported delay minutes here, that single category outweighs weather by 10 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 36,551 reported delay minutes.

37% 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 14,000 minutes out of 37,000, against a national NAS share of 21%.

Cancellations are rare at 0.73%, 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

8.3% 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.

The 533 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 71.1% on time across 2,338 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 2,341 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 MCI to DEN

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 87.0% on time and July 57.7%, a swing of 29 points. If the dates move at all, move them out of July before you think about anything else. 2,316 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