Carrier route record
WNSAT→LAS
Southwest Airlines · San Antonio to Las Vegas
- Flights
- 1,571
- Period
- July 2025 to June 2026
- Share of route
- 76%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on SAT to LAS lands a B+, 4 points better than the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That is a workable record, not a spotless one. That rests on 1,571 flights, with a median arrival 7 minutes early.
Set against the rest of the country, Southwest's SAT to LAS record is 4 points better than the US average of 77.6%. That gap is worth roughly 40 fewer late arrivals for every thousand flights.
Key figures
On time
81.6%
Arrivals under 15 minutes late, of 1,561 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.38%
National rate is 1.81%
Whole route
81.5%
Every carrier on SAT to LAS, 2,059 flights
These figures cover 1,571 flights between July 2025 and June 2026. The median arrival is 7 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 SAT to LAS
Southwest flew 1,571 of the 2,059 flights on SAT to LAS, most of the route. Its 81.6% on time is about level with the route as a whole at 81.5%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Spirit at 83.7% to Frontier at 79.4%. Two 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 |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 210 | 83.7% | 103 min | 0.48% | B+ |
| Southwest Airlines (this page) | 1,571 | 81.6% | 53 min | 0.38% | B+ |
| Frontier Airlinesthin sample | 278 | 79.4% | 68 min | 1.44% | B |
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 36 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–8am356 flights95.5%
- 8am–11am213 flights96.7%
- 11am–2pm320 flights82.7%
- 2pm–5pm242 flights70.7%
- 5pm–8pm259 flights73.3%
- 8pm–5am181 flights60.6%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 60.6% on time, against 96.7% for the 8am–11am 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 356 flights scheduled in it.
Across the year
Southwest on SAT to LAS through the year
June is the worst month at 63.2% on time, 27 points below November, the best at 90.6%. 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. December was the busiest month here, with 150 flights.
Across the week, Tuesday is the strongest day at 90.2% on time and Friday the weakest at 72.1%. 18 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 51% of the 15,000 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.
- 51%Late-arriving aircraft
- 26%Carrier
- 19%National Airspace System
- 5%Extreme weather
- 0%Security
51% 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 15,000 reported delay minutes here, that single category outweighs weather by 11 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 15,210 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 96.7% on time here.
Cancellations are rare at 0.38%, 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
5.3% 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 55 minutes, which a normal layover absorbs.
The 1,069 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 73.3% on time across 1,564 flights, 8 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 8 points of difference.
The sample behind these figures is 1,571 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 SAT to LAS
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 90.6% on time and June 63.2%, a swing of 27 points. If the dates move at all, move them out of June before you think about anything else. 1,561 completed flights over 12 months sit behind that.
Related
Where to go next
- SAT to LAS, every carrier
- Southwest on LAS to SAT, the return leg
- Spirit Airlines on SAT to LAS83.7%
- Frontier Airlines on SAT to LAS79.4%
- Southwest Airlines network-wide record
- San Antonio International (SAT) delay statistics
- Harry Reid International (LAS) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.