Carrier route record

WNCLT→STL

Southwest Airlines · Charlotte to St. Louis

Flights: 264
Period: July 2025 to June 2026
Share of route: 14%
Carriers: 3

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

Southwest on CLT to STL lands a B, 5 points better than the national rate of 77.6%. About one flight in six 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 264 flights, with a median arrival 4 minutes early.

Set against the rest of the country, Southwest's CLT to STL record is 5 points better than the US average of 77.6%. That gap is worth roughly 48 fewer late arrivals for every thousand flights.

On time

82.4%

Arrivals under 15 minutes late, of 261 completed flights

Avg delay

68 min

Across delayed arrivals only, not all flights

Cancelled

1.14%

National rate is 1.81%

Whole route

78.7%

Every carrier on CLT to STL, 1,826 flights

These figures cover 264 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 CLT to STL

Southwest flew 264 of the 1,826 flights on CLT to STL, about 14% of it. Its 82.4% on time is 4 points better than the route as a whole, which runs 78.7%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from PSA at 88.4% to American at 77.6%. 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.

On-time performance by carrier on CLT to STL
Airline	Flights	On time	Avg delay	Cancelled	Grade
PSA Airlinesthin sample	75	88.4%	71 min	6.67%	A−
Southwest Airlines (this page)thin sample	264	82.4%	68 min	1.14%	B
American Airlines	1,487	77.6%	70 min	1.28%	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 15 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–8am—
8am–11am48 flights89.4%
11am–2pm78 flights87.2%
2pm–5pm50 flights82.0%
5pm–8pm64 flights74.2%
8pm–5am24 flights—

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 89.4% of the time, against 74.2% for the evening window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 78 flights scheduled in it.

Across the year

Southwest on CLT to STL through the year

Jul–Sep 202592 flights78.0%
Oct–Dec 202583 flights79.5%
Jan–Mar 202658 flights89.3%
Apr–Jun 202631 flights90.3%

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 82.4% on time across 264 flights.

Southwest on CLT to STL did not run the same all year. Its best quarter was Apr–Jun 2026 at 90.3% on time and its weakest Jul–Sep 2025 at 78.0%, a swing of 12 points on roughly 66 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Tuesday is the strongest day at 87.8% on time and Thursday the weakest at 71.1%. 17 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 55% of the 3,107 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
55%
Carrier
39%
National Airspace System
5%

55% 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 3,107 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 3,107 reported delay minutes.

The largest share of delay minutes, 39%, 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 1,224 of the 3,107 delay minutes reported here.

Cancellations sit at 1.14% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

6.9% 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 about an hour, which a normal layover absorbs.

The 575 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 is a different operation and performs like one: it runs 76.2% on time across 262 flights, 6 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.

One caution: this is a thin sample. 264 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 CLT to STL

Put together: treat all of this as provisional. 264 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 82.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 261 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