Carrier route record
WNLGA→STL
Southwest Airlines · New York to St. Louis
- Flights
- 1,390
- Period
- July 2025 to June 2026
- Share of route
- 53%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on LGA to STL sits in the middle of the pack with a C−. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 1,390 flights, with a median arrival 5 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on LGA 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
73.7%
Arrivals under 15 minutes late, of 1,344 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
3.02%
National rate is 1.81%
Whole route
75.6%
Every carrier on LGA to STL, 2,644 flights
These figures cover 1,390 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Southwest against every carrier on LGA to STL
Southwest flew 1,390 of the 2,644 flights on LGA to STL, most of the route. Its 73.7% on time is 2 points worse than the route as a whole, which runs 75.6%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 89.3% to Southwest at 73.7%. 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 |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 28 | 89.3% | 20 min | 0.00% | A+ |
| Republic Airways | 1,226 | 77.6% | 74 min | 5.22% | B− |
| Southwest Airlines (this page) | 1,390 | 73.7% | 69 min | 3.02% | C− |
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 half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am269 flights93.5%
- 8am–11am329 flights83.3%
- 11am–2pm116 flights77.7%
- 2pm–5pm370 flights63.2%
- 5pm–8pm305 flights56.2%
- 8pm–5am1 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: 56.2% on time, against 93.5% for the 5am–8am 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 2pm–5pm window is the busiest, with 370 flights scheduled in it.
Across the year
Southwest on LGA to STL through the year
July is the worst month at 58.9% on time, 28 points below January, the best at 86.7%. 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. December was the busiest month here, with 122 flights.
Across the week, Friday is the strongest day at 77.2% on time and Sunday the weakest at 66.5%. 11 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 49% of the 24,000 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.
- 49%Late-arriving aircraft
- 23%Carrier
- 22%National Airspace System
- 4%Extreme weather
- 1%Security
49% 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 24,000 reported delay minutes here, that single category outweighs weather by 11 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 24,280 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.5% on time here.
Cancellations run at 3.02%, against 1.81% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 888 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 70.4% on time across 1,390 flights, 3 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 3 points of difference.
The sample behind these figures is 1,390 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking Southwest on LGA to STL
Put together: the delay figures matter less here than the 3.02% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 1,344 completed flights over 12 months sit behind that.
Related
Where to go next
- LGA to STL, every carrier
- Southwest on STL to LGA, the return leg
- Republic Airways on LGA to STL77.6%
- Southwest Airlines network-wide record
- LaGuardia (LGA) delay statistics
- St. Louis Lambert International (STL) delay statistics
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
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.