Carrier route record

WNLAX→SAT

Southwest Airlines · Los Angeles to San Antonio

Flights: 337
Period: July 2025 to June 2026
Share of route: 18%
Carriers: 4

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.

Southwest on LAX to SAT sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land roughly 45 minutes behind schedule. That rests on 337 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 697 at 86.0% on time.

The national on-time rate over the same period is 77.6%, so Southwest on LAX to SAT runs 9 points behind the country as a whole. Across a thousand flights that is about 91 extra late arrivals.

On time

68.5%

Arrivals under 15 minutes late, of 337 completed flights

Avg delay

43 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

Whole route

82.1%

Every carrier on LAX to SAT, 1,881 flights

These figures cover 337 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Southwest against every carrier on LAX to SAT

Southwest flew 337 of the 1,881 flights on LAX to SAT, about 18% of it. Its 68.5% on time is 14 points worse than the route as a whole, which runs 82.1%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from SkyWest at 86.0% to Southwest at 68.5%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The two carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on LAX to SAT
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	697	86.0%	67 min	0.29%	A+
Spirit Airlinesthin sample	163	85.4%	85 min	2.45%	A
Delta Air Lines	684	84.1%	77 min	0.44%	B+
Southwest Airlines (this page)thin sample	337	68.5%	43 min	0.00%	C+

No carrier stands out. SkyWest tops the table at 86.0%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 27 points, against 2 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am11 flights—
8am–11am122 flights76.2%
11am–2pm112 flights70.5%
2pm–5pm73 flights49.3%
5pm–8pm19 flights—
8pm–5am—

Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 76.2% of the time, against 49.3% for the afternoon window. That is 27 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 122 flights scheduled in it.

Across the year

Southwest on LAX to SAT through the year

Darker means more delays. Figures are on-time percentages.October best, June worst

June is the worst month at 43.3% on time, 50 points below October, the best at 93.5%. 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 33 flights.

Across the week, Wednesday is the strongest day at 79.1% on time and Sunday the weakest at 52.0%. 27 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 47% of the 4,514 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.

Late-arriving aircraft
47%
Carrier
43%
National Airspace System
10%

47% 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 4,514 reported delay minutes here, that single category outweighs weather by 47 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 4,514 reported delay minutes.

The largest share of delay minutes, 43%, 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 1,925 of the 4,514 delay minutes reported here.

Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.7% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 1,211 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 73.2% on time across 337 flights, 5 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 5 points of difference.

One caution: this is a thin sample. 337 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 LAX to SAT

Put together: treat all of this as provisional. 337 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 68.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 337 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures