Carrier route record
WNMCI→ATL
Southwest Airlines · Kansas City to Atlanta
- Flights
- 365
- Period
- July 2025 to June 2026
- Share of route
- 11%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on MCI to ATL lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. 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 MCI to ATL from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.8%
Arrivals under 15 minutes late, of 363 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
0.27%
National rate is 1.81%
Whole route
87.4%
Every carrier on MCI to ATL, 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 MCI to ATL
Southwest flew 365 of the 3,281 flights on MCI to ATL, about 11% of it. Its 78.8% on time is 9 points worse than the route as a whole, which runs 87.4%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Delta at 90.1% to Frontier at 60.6%. One 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 2,759 | 90.1% | 74 min | 1.52% | A |
| Southwest Airlines (this page) | 365 | 78.8% | 59 min | 0.27% | B+ |
| Frontier Airlinesthin sample | 157 | 60.6% | 86 min | 1.27% | D |
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 19 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–8am1 flights—
- 8am–11am68 flights85.1%
- 11am–2pm135 flights87.4%
- 2pm–5pm153 flights68.4%
- 5pm–8pm8 flights—
- 8pm–5am—
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 87.4% on time, ahead of 2pm–5pm at 68.4%. 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 153 flights scheduled in it.
Across the year
Southwest on MCI to ATL through the year
September is the best month on the calendar at 93.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. January was the busiest month here, with 31 flights.
Across the week, Thursday is the strongest day at 86.5% on time and Sunday the weakest at 70.6%. 16 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 61% of the 4,561 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.
- 61%Late-arriving aircraft
- 25%Carrier
- 13%National Airspace System
- 1%Extreme weather
- 0%Security
61% 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 4,561 reported delay minutes here, that single category outweighs weather by 55 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 4,561 reported delay minutes.
Cancellations are rare at 0.27%, 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
6.1% 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 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 75.9% 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 MCI to ATL
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 78.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 363 completed flights over 12 months sit behind that.
Related
Where to go next
- MCI to ATL, every carrier
- Southwest on ATL to MCI, the return leg
- Delta Air Lines on MCI to ATL90.1%
- Frontier Airlines on MCI to ATL60.6%
- Southwest Airlines network-wide record
- Kansas City International (MCI) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) 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.