Route reliability record
LAS→STL
Las Vegas to St. Louis
- Flights
- 2,101
- Period
- September 2025 to August 2026
- Distance
- 1,371 mi
- Carriers
- 2
This route lands a B+, about a point better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,101 LAS to STL flights, with a median arrival 5 minutes early.
Best time to fly LAS to STL: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 93.6% of the time and Saturday flights 83.4%, against 78.1% for the route overall.
The US average over the same twelve months is 77.3%, 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
78.1%
Arrivals under 15 minutes late, of 2,088 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.48%
National rate is 1.89%
Best carrier
Southwest
77.3% on time across 1,784 flights
These figures cover 2,101 flights between September 2025 and August 2026. The median arrival is 5 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
Which airline is most reliable on LAS 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 |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 317 | 82.5% | 68 min | 2.21% | B |
| Southwest Airlines | 1,784 | 77.3% | 55 min | 0.17% | B+ |
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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 33 points, against half a point between the best and worst carrier.
- 5am–8am436 flights93.6%
- 8am–11am374 flights88.1%
- 11am–2pm379 flights73.3%
- 2pm–5pm459 flights70.9%
- 5pm–8pm380 flights67.4%
- 8pm–5am73 flights60.3%
Scale runs 50% to 100%.
The 8pm–5am window is where this operation falls apart: 60.3% on time, against 93.6% 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 459 flights scheduled in it.
Explore
Filter LAS to STL by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On LAS to STL, the best departure window is 5am–8am at 93.6% on time and the worst is 8pm–5am at 60.3%, a wide gap of 33.3 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.6%
- 8–11am88.1%
- 11am–2pm73.3%
- 2–5pm70.9%
- 5–8pm67.4%
- 8pm–5am60.3%
best all US flightsScale 50% to 100%.
Across the year
When delays peak on this route
This route's year swings by 18 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.
July is the worst month at 66.7% on time, 18 points below January, the best at 85.1%. 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. March was the busiest month here, with 208 flights.
Across the week, Saturday is the strongest day at 83.4% on time and Sunday the weakest at 74.0%, a spread of 9 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 54% of the 26,000 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Late-arriving aircraft
- 38%Carrier
- 8%National Airspace System
- 0%Extreme weather
- 0%Security
54% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 26,000 reported delay minutes here, that single category outweighs weather by 54 to one. The split is drawn from 25,817 reported delay minutes.
The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 9,733 of the 26,000 delay minutes reported here.
Cancellations are rare at 0.48%, 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 actually costs
6.2% 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 about an hour, which a normal layover absorbs.
The 1,371 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.
The return leg is a different operation and performs like one: it runs 74.9% on time across 2,107 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 2,101 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.
Work out the risk of missing a connection in STL after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 85.1% on time and July 66.7%, a swing of 18 points. If the dates move at all, move them out of July before you think about anything else. 2,088 completed flights over 12 months sit behind that.
Common questions
LAS to STL questions
How often is LAS to STL delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.9% of the 2,101 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is LAS to STL compared with the rest of the country?
78.1% of flights arrive on time here against a national 77.3%, a difference of about a point in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on LAS to STL?
The 5am–8am departure window is the strongest at 93.6% on time. The 8pm–5am window is the weakest at 60.3%, 33 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 July delays on LAS to STL?
July is the weakest month at 66.7% on time, compared with 85.1% in January. Across the year that is 18 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 LAS — the return legseparate record
- Harry Reid International (LAS) delay statistics
- St. Louis Lambert International (STL) delay statistics
- Frontier Airlines on LAS to STL82.5%
- Southwest Airlines on LAS to STL77.3%
- LAS to LAX, a related route77.9%
- DEN to STL, a related route77.7%
- LAS to DEN, a related route76.5%
- Frontier Airlines on-time record82.5%
- Southwest Airlines on-time record77.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. LAS to STL and STL to LAS 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.