Carrier performance at one airport
WN→SAT
Southwest Airlines at San Antonio International
- Departures
- 15,321
- Period
- July 2025 to June 2026
- Routes
- 18
- Rank here
- #5 of 9
Southwest Airlines at San Antonio lands a B+, 3 points better than the national rate of 77.6%. 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 15,321 flights, of which Delta Air Lines flew 6,845 at 86.0% on time.
Measured against the airport rather than the country, Southwest Airlines runs about a point behind the 81.8% 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
80.6%
15,198 completed departures
Avg delay
53 min
Across delayed flights only
Cancelled
0.55%
At SAT, this carrier only
Rank here
#5
Of 9 carriers clearing the floor at SAT
These figures cover 15,000 flights between July 2025 and June 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 86.0% of the time; Envoy Air manages 73.7%. Sample sizes sit next to every figure, because a two-point gap across 961 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 6,845 | 86.0% | 79 min | 1.42% | A |
| SkyWest Airlines | 1,624 | 84.8% | 111 min | 1.42% | B |
| United Airlines | 5,667 | 83.4% | 73 min | 0.72% | B+ |
| American Airlines | 7,481 | 80.6% | 110 min | 2.58% | B |
| Southwest Airlines (this page) | 15,321 | 80.6% | 53 min | 0.55% | B+ |
| Spirit Airlines | 988 | 80.1% | 85 min | 3.14% | B− |
| Frontier Airlines | 903 | 77.4% | 87 min | 0.78% | B+ |
| Alaska Airlines | 558 | 77.0% | 56 min | 1.43% | B |
| Envoy Air | 961 | 73.7% | 71 min | 2.81% | C |
Spirit Airlines cancels 3.1% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after 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 | 2,728 | 83.2% | 61 min | 1.25% | B |
| SAT to LAS · Las Vegas | 1,571 | 81.6% | 53 min | 0.38% | B+ |
| SAT to DEN · Denver | 1,432 | 80.8% | 53 min | 0.28% | B+ |
| SAT to PHX · Phoenix | 1,390 | 83.3% | 51 min | 0.22% | B+ |
| SAT to HOU · Houston | 1,378 | 74.5% | 50 min | 0.29% | C+ |
| SAT to BNA · Nashville | 938 | 79.8% | 52 min | 0.53% | B+ |
| SAT to ELP · El Paso | 765 | 79.8% | 56 min | 0.13% | B+ |
| SAT to MCO · Orlando | 747 | 77.9% | 57 min | 0.40% | B+ |
| SAT to BWI · Baltimore | 735 | 81.0% | 55 min | 1.63% | B |
| SAT to MDW · Chicago | 673 | 78.2% | 44 min | 1.04% | B |
| SAT to SAN · San Diego | 610 | 78.7% | 54 min | 0.33% | B+ |
| SAT to STL · St. Louis | 547 | 85.7% | 52 min | 0.00% | A+ |
| SAT to TPA · Tampa | 375 | 79.1% | 55 min | 0.27% | B+ |
| SAT to MSY · New Orleansthin sample | 350 | 84.0% | 36 min | 0.29% | B+ |
| SAT to LAX · Los Angelesthin sample | 337 | 73.2% | 48 min | 0.00% | C+ |
| SAT to ATL · Atlantathin sample | 318 | 79.9% | 46 min | 0.31% | B+ |
| SAT to MCI · Kansas Citythin sample | 274 | 81.3% | 60 min | 0.00% | B+ |
| SAT to OKC · Oklahoma Citythin sample | 116 | 91.4% | 47 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 31 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am3,924 flights94.8%
- 8am–11am1,704 flights92.5%
- 11am–2pm3,237 flights82.9%
- 2pm–5pm2,917 flights71.7%
- 5pm–8pm2,577 flights64.6%
- 8pm–5am962 flights63.5%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 63.5% on time, against 94.8% 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 3,924 flights scheduled in it.
Across the year
Seasonal pattern
June is the worst month at 67.1% on time, 19 points below September, the best at 86.3%. 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. July was the busiest month here, with 1,438 flights.
Delay causes
What holds this operation up
- 52%Late-arriving aircraft
- 22%Carrier
- 22%National Airspace System
- 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 156,000 reported delay minutes here, that single category outweighs weather by 16 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 155,922 reported delay minutes.
Cancellations are rare at 0.55%, 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.
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 are the roughly 55 minutes kind, which a normal layover absorbs.
15,321 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: the calendar is the biggest lever here, not the carrier or the hour. September runs 86.3% on time and June 67.1%, a swing of 19 points. If the dates move at all, move them out of June before you think about anything else. 15,198 completed flights over 12 months sit behind that.
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 19.4% of the 15,321 flights in this analysis, against 22.4% 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 86.0% on time across 6,845 flights. Envoy Air is at the other end on 73.7%, 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 94.8% on time. The 8pm–5am window is the weakest at 63.5%, 31 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 June delays on Southwest Airlines at SAT?
June is the weakest month at 67.1% on time, compared with 86.3% in September. Across the year that is 19 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, July 2025 to June 2026. Updated monthly. How this data is collected.