Carrier route record
WNSTL→LGA
Southwest Airlines · St. Louis to New York
- 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 STL to LGA sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,390 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.6%, so Southwest on STL to LGA runs 7 points behind the country as a whole. Across a thousand flights that is about 72 extra late arrivals.
Key figures
On time
70.4%
Arrivals under 15 minutes late, of 1,337 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
3.17%
National rate is 1.81%
Whole route
74.9%
Every carrier on STL to LGA, 2,645 flights
These figures cover 1,390 flights between July 2025 and June 2026. Beyond the headline rate, 8.6% 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 STL to LGA
Southwest flew 1,390 of the 2,645 flights on STL to LGA, most of the route. Its 70.4% on time is 5 points worse than the route as a whole, which runs 74.9%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Republic at 80.3% to SkyWest at 66.7%. 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 |
|---|---|---|---|---|---|
| Republic Airways | 1,227 | 80.3% | 85 min | 4.56% | B− |
| Southwest Airlines (this page) | 1,390 | 70.4% | 57 min | 3.17% | C− |
| SkyWest Airlinesthin sample | 28 | 66.7% | 78 min | 0.00% | 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 38 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–8am340 flights92.7%
- 8am–11am123 flights79.7%
- 11am–2pm263 flights67.4%
- 2pm–5pm207 flights62.2%
- 5pm–8pm238 flights55.2%
- 8pm–5am219 flights57.7%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 55.2% on time, against 92.7% 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 5am–8am window is the busiest, with 340 flights scheduled in it.
Across the year
Southwest on STL to LGA through the year
Delays peak in March, when the on-time rate falls to 57.7%. January is the strongest month at 84.1%. Moving a flexible trip across that boundary buys 26 points. December was the busiest month here, with 122 flights.
Across the week, Wednesday is the strongest day at 79.2% on time and Sunday the weakest at 58.8%. 20 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 22,000 reported delay minutes.
- 36%National Airspace System
- 35%Late-arriving aircraft
- 24%Carrier
- 4%Extreme weather
- 1%Security
35% 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 22,000 reported delay minutes here, that single category outweighs weather by 8 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 22,422 reported delay minutes.
36% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 8,045 minutes out of 22,000, against a national NAS share of 21%.
Cancellations run at 3.17%, against 1.81% nationally. That is about 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
8.6% 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 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 73.7% on time across 1,390 flights, 3 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 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 STL to LGA
Put together: the delay figures matter less here than the 3.17% cancellation rate. A late arrival costs you about 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. 1,337 completed flights over 12 months sit behind that.
Related
Where to go next
- STL to LGA, every carrier
- Southwest on LGA to STL, the return leg
- Republic Airways on STL to LGA80.3%
- Southwest Airlines network-wide record
- St. Louis Lambert International (STL) delay statistics
- LaGuardia (LGA) 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.