Carrier route record
WNATL→LAS
Southwest Airlines · Atlanta to Las Vegas
- Flights
- 719
- Period
- July 2025 to June 2026
- Share of route
- 15%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on ATL to LAS 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 719 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 3,329 at 77.3% on time.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on ATL to LAS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.2%
Arrivals under 15 minutes late, of 716 completed flights
Avg delay
48 min
Across delayed arrivals only, not all flights
Cancelled
0.42%
National rate is 1.81%
Whole route
75.9%
Every carrier on ATL to LAS, 4,796 flights
These figures cover 719 flights between July 2025 and June 2026. The median arrival is 4 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
Southwest against every carrier on ATL to LAS
Southwest flew 719 of the 4,796 flights on ATL to LAS, about 15% of it. Its 77.2% on time is about level with the route as a whole at 75.9%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Spirit at 82.2% to Frontier at 63.3%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 77.3% of the time; Frontier Airlines manages 63.3%. Sample sizes sit next to every figure, because a two-point gap across 562 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 186 | 82.2% | 68 min | 0.54% | B+ |
| Delta Air Lines | 3,329 | 77.3% | 55 min | 0.60% | B+ |
| Southwest Airlines (this page) | 719 | 77.2% | 48 min | 0.42% | B+ |
| Frontier Airlines | 562 | 63.3% | 88 min | 2.31% | D |
The spread between Delta and Frontier is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.
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 35 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am337 flights93.5%
- 8am–11am10 flights—
- 11am–2pm13 flights—
- 2pm–5pm33 flights60.6%
- 5pm–8pm267 flights62.4%
- 8pm–5am59 flights58.6%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 58.6% 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 5am–8am window is the busiest, with 337 flights scheduled in it.
Across the year
Southwest on ATL to LAS through the year
June is the worst month at 62.7% on time, 26 points below November, the best at 89.1%. 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 62 flights.
Across the week, Saturday is the strongest day at 85.3% on time and Thursday the weakest at 70.9%. 14 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 54% of the 7,742 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.
- 54%Late-arriving aircraft
- 23%Carrier
- 17%National Airspace System
- 6%Extreme weather
54% 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 7,742 reported delay minutes here, that single category outweighs weather by 9 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 7,742 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 are rare at 0.42%, 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 costs
5.0% 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 1,747 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 82.9% on time across 720 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 719 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.
What to do with this
Booking Southwest on ATL to LAS
Put together: treat all of this as provisional. 719 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 77.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 716 completed flights over 12 months sit behind that.
Related
Where to go next
- ATL to LAS, every carrier
- Southwest on LAS to ATL, the return leg
- Spirit Airlines on ATL to LAS82.2%
- Delta Air Lines on ATL to LAS77.3%
- Frontier Airlines on ATL to LAS63.3%
- Southwest Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Harry Reid International (LAS) delay statistics
- Same route, different airline: where the carrier you pick matters most
- 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.