Carrier performance at one airport
WN→SAT
Southwest Airlines at San Antonio International
- Departures
- 15,433
- Period
- June 2025 to May 2026
- Routes
- 18
- Rank here
- #4 of 9
Southwest Airlines at San Antonio lands a B+, 4 points better than the national rate of 77.4%. About one flight in five arrive 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 15,433 flights, of which Delta Air Lines flew 6,851 at 85.3% on time.
Measured against the airport rather than the country, Southwest Airlines runs half a point behind the 81.9% weighted average across all carriers at SAT. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
81.4%
15,313 completed departures
Avg delay
54 min
Across delayed flights only
Cancelled
0.54%
At SAT, this carrier only
Rank here
#4
Of 9 carriers clearing the floor at SAT
These figures cover 15,000 flights between June 2025 and May 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.
Against the competition
Every carrier at SAT, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 85.3% of the time; Envoy Air manages 73.8%. Sample sizes sit next to every figure, because a two-point gap across 878 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 6,851 | 85.3% | 79 min | 1.42% | A |
| SkyWest Airlines | 1,631 | 83.8% | 110 min | 1.35% | B |
| United Airlines | 5,684 | 83.4% | 76 min | 0.83% | B+ |
| Southwest Airlines (this page) | 15,433 | 81.4% | 54 min | 0.54% | B+ |
| American Airlines | 7,508 | 80.8% | 107 min | 2.45% | B |
| Spirit Airlines | 1,205 | 79.5% | 81 min | 2.82% | B |
| Frontier Airlines | 879 | 77.2% | 92 min | 1.25% | B |
| Alaska Airlines | 558 | 74.9% | 53 min | 1.43% | C |
| Envoy Air | 878 | 73.8% | 72 min | 2.62% | C |
Delta leads Envoy by 12 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Route by route
Where Southwest Airlines flies from SAT
Southwest Airlines operates 18 routes out of SAT with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SAT to DAL · Dallas | 2,717 | 83.8% | 60 min | 1.18% | B |
| SAT to LAS · Las Vegas | 1,574 | 83.0% | 55 min | 0.32% | B+ |
| SAT to DEN · Denver | 1,433 | 81.8% | 54 min | 0.35% | B+ |
| SAT to HOU · Houston | 1,409 | 74.1% | 49 min | 0.35% | C+ |
| SAT to PHX · Phoenix | 1,387 | 84.4% | 54 min | 0.29% | B+ |
| SAT to BNA · Nashville | 932 | 81.3% | 51 min | 0.64% | B+ |
| SAT to ELP · El Paso | 781 | 80.1% | 62 min | 0.00% | B+ |
| SAT to MCO · Orlando | 764 | 77.3% | 57 min | 0.26% | B+ |
| SAT to BWI · Baltimore | 738 | 81.6% | 55 min | 1.76% | B |
| SAT to MDW · Chicago | 685 | 80.6% | 43 min | 0.88% | B+ |
| SAT to SAN · San Diego | 609 | 78.6% | 53 min | 0.33% | B+ |
| SAT to STL · St. Louis | 547 | 87.2% | 56 min | 0.00% | A+ |
| SAT to TPA · Tampa | 380 | 80.2% | 61 min | 0.26% | B+ |
| SAT to MSY · New Orleansthin sample | 355 | 83.3% | 35 min | 0.28% | B+ |
| SAT to LAX · Los Angelesthin sample | 337 | 75.6% | 43 min | 0.00% | B+ |
| SAT to ATL · Atlantathin sample | 329 | 80.5% | 47 min | 0.30% | B+ |
| SAT to MCI · Kansas Citythin sample | 279 | 82.3% | 55 min | 0.00% | B+ |
| SAT to OKC · Oklahoma Citythin sample | 140 | 90.0% | 43 min | 0.00% | A+ |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 30 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am3,916 flights95.2%
- 8am–11am1,757 flights92.5%
- 11am–2pm3,274 flights83.6%
- 2pm–5pm2,901 flights73.1%
- 5pm–8pm2,568 flights65.6%
- 8pm–5am1,017 flights64.8%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 64.8% on time, against 95.2% 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.
Across the year
Seasonal pattern
September is the best month on the calendar at 86.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back.
Delay causes
What holds this operation up
- 52%Late-arriving aircraft
- 23%National Airspace System
- 21%Carrier
- 3%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 153,000 reported delay minutes here, that single category outweighs weather by 18 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.
Cancellations are rare at 0.54%, below the national 1.80% 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.
5.1% of arrivals land an hour or more late, close to the national 8.2%. 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 roughly 55 minutes kind, which a normal layover absorbs.
15,433 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
Put together: avoid the 8pm–5am departure. It runs 64.8% on time against 95.2% for the 5am–8am slot, and that 30 points is the largest single thing you control here. Delta Air Lines is the strongest operator if the fares are close.
Common questions
Southwest Airlines at SAT
How often is Southwest Airlines at SAT 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 18.6% of the 15,433 flights in this analysis, against 22.6% nationally. Delayed flights are late by roughly 55 minutes on average.
Which airline is most reliable on Southwest Airlines at SAT?
Delta Air Lines leads at 85.3% on time across 6,851 flights. Envoy Air is at the other end on 73.8%, a gap of 12 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Southwest Airlines at SAT?
The 5am–8am departure window is the strongest at 95.2% on time. The 8pm–5am window is the weakest at 64.8%, 30 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 May delays on Southwest Airlines at SAT?
May is the weakest month at 75.9% on time, compared with 86.3% in September. Across the year that is 10 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
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.