Carrier route record

WNSTL→CLT

Southwest Airlines · St. Louis to Charlotte

Flights: 262
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 STL to CLT lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 262 flights, with a median arrival 1 minute late.

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

On time

76.2%

Arrivals under 15 minutes late, of 261 completed flights

Avg delay

48 min

Across delayed arrivals only, not all flights

Cancelled

0.38%

National rate is 1.81%

Whole route

83.5%

Every carrier on STL to CLT, 1,827 flights

These figures cover 262 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Southwest against every carrier on STL to CLT

Southwest flew 262 of the 1,827 flights on STL to CLT, about 14% of it. Its 76.2% on time is 7 points worse than the route as a whole, which runs 83.5%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from PSA at 87.1% to Southwest at 76.2%. 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 STL to CLT
Airline	Flights	On time	Avg delay	Cancelled	Grade
PSA Airlinesthin sample	75	87.1%	228 min	6.67%	A−
American Airlines	1,490	84.6%	109 min	1.21%	B
Southwest Airlines (this page)thin sample	262	76.2%	48 min	0.38%	B+

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 262 flights.

5am–8am—
8am–11am2 flights—
11am–2pm16 flights—
2pm–5pm210 flights75.1%
5pm–8pm34 flights73.5%
8pm–5am—

Scale runs 65% to 80%. Rows with fewer than 30 flights show a dash.

The 2pm–5pm window is the strongest at 75.1% on time. The full set of windows spans 2 points.

Across the year

Southwest on STL to CLT through the year

Jul–Sep 202590 flights77.8%
Oct–Dec 202583 flights67.5%
Jan–Mar 202658 flights89.5%
Apr–Jun 202631 flights71.0%

Scale runs 60% 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 76.2% on time across 262 flights.

Southwest on STL to CLT did not run the same all year. Its best quarter was Jan–Mar 2026 at 89.5% on time and its weakest Oct–Dec 2025 at 67.5%, a swing of 22 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 87.5% on time and Thursday the weakest at 64.1%. 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 57% of the 2,966 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
57%
Carrier
30%
National Airspace System
12%
Security
1%
Extreme weather
1%

57% 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 2,966 reported delay minutes here, that single category outweighs weather by 57 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 2,966 reported delay minutes.

Cancellations are rare at 0.38%, 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

Badly late arrivals are rare here: only 3.8% 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 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 82.4% on time across 264 flights, 6 points above 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. 262 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 STL to CLT

Put together: treat all of this as provisional. 262 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 76.2% 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