Carrier route record
WNMSP→STL
Southwest Airlines · Minneapolis to St. Louis
- Flights
- 653
- Period
- September 2025 to August 2026
- Share of route
- 33%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on MSP to STL lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That rests on 653 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 906 at 79.9% on time.
The US average over the same twelve months is 77.3%, so there is little to separate Southwest on MSP to STL from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.2%
Arrivals under 15 minutes late, of 648 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.31%
National rate is 1.89%
Whole route
79.6%
Every carrier on MSP to STL, 1,958 flights
These figures cover 653 flights between September 2025 and August 2026. The median arrival is 9 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.
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Carrier by carrier
Southwest against every carrier on MSP to STL
Southwest flew 653 of the 1,958 flights on MSP to STL, about 33% of it. Its 81.2% on time is 2 points better than the route as a whole, which runs 79.6%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from Southwest at 81.2% to SkyWest at 76.3%.
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines (this page) | 653 | 81.2% | 51 min | 0.31% | B+ |
| Delta Air Lines | 906 | 79.9% | 63 min | 1.10% | B |
| SkyWest Airlines | 399 | 76.3% | 85 min | 1.25% | B |
No carrier stands out. Delta tops the table at 79.9%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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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 4 points between the best and worst carrier.
- 5am–8am224 flights96.4%
- 8am–11am124 flights96.7%
- 11am–2pm15 flights—
- 2pm–5pm120 flights67.5%
- 5pm–8pm148 flights59.9%
- 8pm–5am22 flights—
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 59.9% on time, against 96.7% for the 8am–11am 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 224 flights scheduled in it.
Across the year
Southwest on MSP to STL through the year
Delays peak in September, when the on-time rate falls to 69.6%. January is the strongest month at 92.1%. Moving a flexible trip across that boundary buys 23 points. July was the busiest month here, with 62 flights.
Across the week, Saturday is the strongest day at 91.2% on time and Monday the weakest at 75.2%, a spread of 16 points.
Arrival by arrival
How late Southwest on MSP to STL runs when it is late
Southwest on MSP to STL often beats the schedule: 230 of 648 completed flights, 35%, arrived 15 minutes or more early. The 122 late arrivals split 51 under half an hour, 36 between 30 and 60 minutes, and 35 an hour or more.
- 15+ min early230 flights35.5%
- Within 15 min296 flights45.7%
- 15–29 min late51 flights7.9%
- 30–59 min late36 flights5.6%
- 1–2 hours late26 flights4.0%
- 2+ hours late9 flights1.4%
Scale runs 0% to 100%.
Share of 648 completed flights by arrival against schedule.
42 of 154 late departures made up the time and arrived on time, 27% of them. Only 10 left on time and still arrived late.
The worst days
Worst days for Southwest on MSP to STL
The latest arrival of the period was on 6 March 2026, 5 hours 15 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 March 2026 | 5 hours 15 minutes | Late-arriving aircraft |
| 28 December 2025 | 3 hours 26 minutes | Late-arriving aircraft |
| 9 May 2026 | 3 hours 10 minutes | Carrier |
| 24 February 2026 | 2 hours 44 minutes | Carrier |
| 18 December 2025 | 2 hours 39 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 64% of the 6,265 delay minutes carriers reported here, and the remaining four split what is left.
- 64%Late-arriving aircraft
- 25%Carrier
- 10%National Airspace System
- 1%Extreme weather
64% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 6,265 reported delay minutes here, that single category outweighs weather by 64 to one. The split is drawn from 6,265 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 96.7% on time here.
Cancellations are rare at 0.31%, below the national 1.89% 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
5.4% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 50 minutes, which a normal layover absorbs.
At 448 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 74.5% on time across 657 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 653 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 MSP to STL
Put together: treat all of this as provisional. 653 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 81.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 648 completed flights over 12 months sit behind that.
Related
Where to go next
- MSP to STL, every carrier
- Southwest on STL to MSP, the return leg
- Delta Air Lines on MSP to STL79.9%
- SkyWest Airlines on MSP to STL76.3%
- Southwest Airlines network-wide record
- Minneapolis-St Paul International (MSP) delay statistics
- St. Louis Lambert International (STL) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.