Carrier route record
WNSAT→LAS
Southwest Airlines · San Antonio to Las Vegas
- Flights
- 1,587
- Period
- September 2025 to August 2026
- Share of route
- 77%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on SAT to LAS lands a B+, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That rests on 1,587 flights, with a median arrival 6 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Southwest on SAT 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
79.3%
Arrivals under 15 minutes late, of 1,578 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.44%
National rate is 1.89%
Whole route
78.8%
Every carrier on SAT to LAS, 2,049 flights
These figures cover 1,587 flights between September 2025 and August 2026. The median arrival is 6 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
Southwest against every carrier on SAT to LAS
Southwest flew 1,587 of the 2,049 flights on SAT to LAS, most of the route. Its 79.3% on time is about level with the route as a whole at 78.8%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Spirit at 81.4% to Frontier at 74.8%. 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 | 157 | 81.4% | 96 min | 0.64% | B+ |
| Southwest Airlines (this page) | 1,587 | 79.3% | 53 min | 0.44% | B+ |
| Frontier Airlinesthin sample | 305 | 74.8% | 69 min | 0.98% | C+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 41 points, against half a point between the best and worst carrier.
- 5am–8am356 flights94.4%
- 8am–11am190 flights96.3%
- 11am–2pm363 flights81.7%
- 2pm–5pm227 flights67.3%
- 5pm–8pm275 flights70.4%
- 8pm–5am176 flights55.4%
Scale runs 45% to 100%.
The 8pm–5am window is where this operation falls apart: 55.4% on time, against 96.3% 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 11am–2pm window is the busiest, with 363 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 89.1% on time and Friday the weakest at 68.2%, a spread of 21 points.
Arrival by arrival
How late Southwest on SAT to LAS runs when it is late
The 326 late arrivals split 136 under half an hour, 99 between 30 and 60 minutes, and 91 an hour or more.
- 15+ min early383 flights24.3%
- Within 15 min869 flights55.1%
- 15–29 min late136 flights8.6%
- 30–59 min late99 flights6.3%
- 1–2 hours late63 flights4.0%
- 2+ hours late28 flights1.8%
Scale runs 0% to 100%.
Share of 1,578 completed flights by arrival against schedule.
120 of 418 late departures made up the time and arrived on time, 29% of them. Only 28 left on time and still arrived late.
The worst days
Worst days for Southwest on SAT to LAS
The latest arrival of the period was on 25 January 2026, 6 hours 22 minutes behind schedule; most of its delay minutes were filed as extreme weather. The five worst days are spread across January, March and October, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 25 January 2026 | 6 hours 22 minutes | Extreme weather |
| 17 January 2026 | 4 hours 32 minutes | Carrier |
| 20 March 2026 | 4 hours 5 minutes | Carrier |
| 10 October 2025 | 4 hours 2 minutes | Late-arriving aircraft |
| 16 March 2026 | 3 hours 31 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 52% of the 17,000 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Late-arriving aircraft
- 25%Carrier
- 18%National Airspace System
- 4%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. Across 17,000 reported delay minutes here, that single category outweighs weather by 13 to one. The split is drawn from 17,109 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 96.3% on time here.
Cancellations are rare at 0.44%, 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 costs
5.8% 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 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.
The return leg is a different operation and performs like one: it runs 72.1% on time across 1,569 flights, 7 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 7 points of difference.
The sample behind these figures is 1,587 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. 1,578 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 LAS81.4%
- Frontier Airlines on SAT to LAS74.8%
- 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 7.05 million flight records
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.