Route reliability record
LAX→STL
Los Angeles to St. Louis
- Flights
- 1,028
- Period
- July 2025 to June 2026
- Distance
- 1,592 mi
- Carriers
- 2
This route lands a B+, level with the national rate of 77.6%. Roughly 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 1,028 LAX to STL flights, with a median arrival 2 minutes early.
Best time to fly LAX to STL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 93.8% of the time and Wednesday flights 87.5%, against 77.0% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.0%
Arrivals under 15 minutes late, of 1,021 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
0.49%
National rate is 1.81%
Best carrier
Southwest
76.3% on time across 674 flights
These figures cover 1,028 flights between July 2025 and June 2026. The median arrival is 2 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
Which airline is most reliable on LAX to STL
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 | 354 | 78.3% | 60 min | 0.56% | B+ |
| Southwest Airlines | 674 | 76.3% | 48 min | 0.45% | B+ |
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 34 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–8am260 flights93.8%
- 8am–11am64 flights81.0%
- 11am–2pm176 flights60.2%
- 2pm–5pm75 flights73.3%
- 5pm–8pm453 flights74.0%
- 8pm–5am—
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 60.2% on time against 93.8% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5pm–8pm window is the busiest, with 453 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 15 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
Delays peak in March, when the on-time rate falls to 67.1%. February is the strongest month at 82.4%. Moving a flexible trip across that boundary buys 15 points. December was the busiest month here, with 103 flights.
Across the week, Wednesday is the strongest day at 87.5% on time and Monday the weakest at 71.6%. 16 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 47% of the 12,000 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.
- 47%Late-arriving aircraft
- 42%Carrier
- 10%National Airspace System
- 1%Extreme weather
47% 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 12,000 reported delay minutes here, that single category outweighs weather by 47 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 12,118 reported delay minutes.
The largest share of delay minutes, 42%, 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 5,113 of the 12,000 delay minutes reported here.
Cancellations are rare at 0.49%, 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 actually costs
6.0% 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 roughly 50 minutes, which a normal layover absorbs.
At 1,592 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 74.0% on time across 1,028 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.
One caution: this is a thin sample. 1,028 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.
Work out the risk of missing a connection in STL after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,028 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 77.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,021 completed flights over 12 months sit behind that.
Common questions
LAX to STL questions
How often is LAX to STL delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.0% of the 1,028 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 50 minutes on average.
How reliable is LAX to STL compared with the rest of the country?
77.0% of flights arrive on time here against a national 77.6%, a difference of half a point against it. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on LAX to STL?
The 5am–8am departure window is the strongest at 93.8% on time. The 11am–2pm window is the weakest at 60.2%, 34 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are March delays on LAX to STL?
March is the weakest month at 67.1% on time, compared with 82.4% in February. Across the year that is 15 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- STL to LAX — the return legseparate record
- Los Angeles International (LAX) delay statistics
- St. Louis Lambert International (STL) delay statistics
- SkyWest Airlines on LAX to STL78.3%
- Southwest Airlines on LAX to STL76.3%
- LAX to SFO, a related route64.8%
- ATL to STL, a related route82.4%
- LAX to JFK, a related route79.1%
- SkyWest Airlines on-time record78.3%
- Southwest Airlines on-time record76.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. LAX to STL and STL to LAX are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.