Route reliability record
LAS→STL
Las Vegas to St. Louis
- Flights
- 2,073
- Period
- July 2025 to June 2026
- Distance
- 1,371 mi
- Carriers
- 2
This route lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 2,073 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 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
79.4%
Arrivals under 15 minutes late, of 2,060 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.43%
National rate is 1.81%
Best carrier
Southwest
78.2% on time across 1,778 flights
These figures cover 2,073 flights between July 2025 and June 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.
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 | 295 | 86.5% | 85 min | 2.03% | A |
| Southwest Airlines | 1,778 | 78.2% | 54 min | 0.17% | 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 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–8am456 flights94.7%
- 8am–11am401 flights88.7%
- 11am–2pm292 flights75.7%
- 2pm–5pm503 flights70.2%
- 5pm–8pm341 flights69.3%
- 8pm–5am80 flights58.2%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 58.2% on time, against 94.7% 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 2pm–5pm window is the busiest, with 503 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 13 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.
June is the worst month at 71.8% on time, 13 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 84.8% on time and Sunday the weakest at 75.0%. 10 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 52% 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.
- 52%Late-arriving aircraft
- 39%Carrier
- 8%National Airspace System
- 0%Extreme weather
- 0%Security
52% 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 52 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 24,037 reported delay minutes.
The largest share of delay minutes, 39%, 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 9,432 of the 24,000 delay minutes reported here.
Cancellations are rare at 0.43%, 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
6.1% 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 are the about an hour kind, 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. 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 sample behind these figures is 2,073 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 this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 85.1% on time and June 71.8%, a swing of 13 points. If the dates move at all, move them out of June before you think about anything else. 2,060 completed flights over 12 months sit behind that.
Common questions
LAS to STL questions
How often is LAS to STL delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.6% of the 2,073 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is LAS to STL compared with the rest of the country?
79.4% of flights arrive on time here against a national 77.6%, a difference of 2 points 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 94.7% on time. The 8pm–5am window is the weakest at 58.2%, 37 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 June delays on LAS to STL?
June is the weakest month at 71.8% on time, compared with 85.1% in January. Across the year that is 13 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
- Harry Reid International (LAS) delay statistics
- St. Louis Lambert International (STL) delay statistics
- Frontier Airlines on-time record86.5%
- Southwest Airlines on-time record78.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
The reverse direction, STL to LAS, does not clear this site’s 365-flight floor and has no page of its own.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.