Carrier route record

WNATL→MCI

Southwest Airlines · Atlanta to Kansas City

Flights: 365
Period: July 2025 to June 2026
Share of route: 11%
Carriers: 4

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

Southwest on ATL to MCI sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 365 flights, with a median arrival 4 minutes early.

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

On time

75.9%

Arrivals under 15 minutes late, of 365 completed flights

Avg delay

50 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

Whole route

82.8%

Every carrier on ATL to MCI, 3,281 flights

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 4 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 ATL to MCI

Southwest flew 365 of the 3,281 flights on ATL to MCI, about 11% of it. Its 75.9% on time is 7 points worse than the route as a whole, which runs 82.8%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from SkyWest at 100.0% to Frontier at 68.6%. Two 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 ATL to MCI
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	1	100.0%	—	0.00%	A+
Delta Air Lines	2,758	84.6%	57 min	1.38%	B
Southwest Airlines (this page)	365	75.9%	50 min	0.00%	B+
Frontier Airlinesthin sample	157	68.6%	77 min	0.64%	C+

Departure window

When Southwest runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 365 flights.

5am–8am—
8am–11am21 flights—
11am–2pm153 flights79.1%
2pm–5pm191 flights73.3%
5pm–8pm—
8pm–5am—

Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 79.1% on time, ahead of 2pm–5pm at 73.3%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 2pm–5pm window is the busiest, with 191 flights scheduled in it.

Across the year

Southwest on ATL to MCI through the year

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

July is the worst month at 58.1% on time, 32 points below April, the best at 90.0%. 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. January was the busiest month here, with 31 flights.

Across the week, Friday is the strongest day at 88.5% on time and Thursday the weakest at 65.4%. 23 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 44% of the 4,428 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
44%
Carrier
44%
National Airspace System
8%
Security
2%
Extreme weather
1%

44% 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 4,428 reported delay minutes here, that single category outweighs weather by 35 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 4,428 reported delay minutes.

The largest share of delay minutes, 44%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,942 of the 4,428 delay minutes reported here.

Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.9% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 692 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 78.8% on time across 365 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 365 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking Southwest on ATL to MCI

Put together: treat all of this as provisional. 365 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 75.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 365 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