Carrier route record

WNMCI→PHX

Southwest Airlines · Kansas City to Phoenix

Flights: 1,635
Period: July 2025 to June 2026
Share of route: 66%
Carriers: 5

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

Southwest on MCI to PHX lands a B+, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That is a workable record, not a spotless one. That rests on 1,635 flights, with a median arrival 2 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate Southwest on MCI to PHX from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

77.0%

Arrivals under 15 minutes late, of 1,624 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.55%

National rate is 1.81%

Whole route

79.1%

Every carrier on MCI to PHX, 2,471 flights

These figures cover 1,635 flights between July 2025 and June 2026. The median arrival is 2 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 MCI to PHX

Southwest flew 1,635 of the 2,471 flights on MCI to PHX, most of the route. Its 77.0% on time is 2 points worse than the route as a whole, which runs 79.1%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Envoy at 90.3% to SkyWest at 75.4%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on MCI to PHX
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Airthin sample	114	90.3%	36 min	0.88%	A+
Frontier Airlinesthin sample	55	83.6%	53 min	0.00%	B+
American Airlines	597	82.7%	119 min	1.17%	B
Southwest Airlines (this page)	1,635	77.0%	54 min	0.55%	B+
SkyWest Airlinesthin sample	70	75.4%	85 min	1.43%	B

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

5am–8am340 flights91.8%
8am–11am284 flights86.5%
11am–2pm260 flights81.5%
2pm–5pm265 flights72.1%
5pm–8pm335 flights63.7%
8pm–5am151 flights55.1%

Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 55.1% on time, against 91.8% 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 340 flights scheduled in it.

Across the year

Southwest on MCI to PHX through the year

Darker means more delays. Figures are on-time percentages.September best, November worst

September is the best month on the calendar at 84.1% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 172 flights.

Across the week, Wednesday is the strongest day at 82.0% on time and Sunday the weakest at 68.5%. 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. Late-arriving aircraft accounts for 53% of the 20,000 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
53%
Carrier
26%
National Airspace System
18%
Extreme weather
3%
Security
1%

53% 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 20,000 reported delay minutes here, that single category outweighs weather by 18 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 20,348 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.8% on time here.

Cancellations are rare at 0.55%, 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

6.0% 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 55 minutes, which a normal layover absorbs.

The 1,044 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 75.0% on time across 1,636 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 1,635 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 PHX

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 84.1% on time and November 71.0%, a swing of 13 points. If the dates move at all, move them out of November before you think about anything else. 1,624 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