San Antonio, TX · departure reliability

SAT

San Antonio International

Departures: 40,454
Period: July 2025 to June 2026
Carriers: 9
US rank: #45 by volume

Terminal building and aircraft stands at a US airport

San Antonio

San Antonio International lands a B, 4 points better than the national rate of 77.6%. Roughly one flight in five arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 40,454 flights, of which Delta Air Lines flew 6,845 at 86.0% on time.

Delta Air Lines is the most reliable of the nine carriers covered here at 86.0% on time across 6,845 flights.

On time

81.8%

Departures arriving under 15 minutes late at their destination

Avg delay

74 min

Across delayed flights only

Cancelled

1.28%

National rate is 1.81%

Best carrier

Delta

86.0% on time here

These figures cover 40,000 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

Which airlines run best out of SAT

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.

On-time performance by carrier departing SAT
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	15,321	80.6%	53 min	0.55%	B+
American Airlines	7,481	80.6%	110 min	2.58%	B
Delta Air Lines	6,845	86.0%	79 min	1.42%	A
United Airlines	5,667	83.4%	73 min	0.72%	B+
SkyWest Airlines	1,624	84.8%	111 min	1.42%	B
Spirit Airlines	988	80.1%	85 min	3.14%	B−
Envoy Air	961	73.7%	71 min	2.81%	C
Frontier Airlines	903	77.4%	87 min	0.78%	B+
Alaska Airlines	558	77.0%	56 min	1.43%	B

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

Busiest routes out of SAT

Route-level records vary far more than the airport average. These are the 25 busiest departures from SAT, each with its own on-time rate against the airport-wide 81.8%.

Busiest routes from SAT by flight volume
Route	Flights	On time	Avg delay	Cancelled	Grade
SAT to DFW · Dallas-Fort Worth	4,382	77.1%	105 min	3.47%	B−
SAT to DEN · Denver	3,027	81.0%	68 min	0.43%	B+
SAT to ATL · Atlanta	3,026	86.1%	72 min	1.55%	A
SAT to DAL · Dallas	2,728	83.2%	61 min	1.25%	B
SAT to PHX · Phoenix	2,512	81.9%	78 min	0.52%	B+
SAT to IAH · Houston	2,410	81.6%	64 min	0.71%	B+
SAT to LAS · Las Vegas	2,059	81.5%	60 min	0.53%	B+
SAT to ORD · Chicago	1,968	76.3%	75 min	2.29%	B
SAT to LAX · Los Angeles	1,881	86.6%	89 min	0.48%	A+
SAT to HOU · Houston	1,378	74.5%	50 min	0.29%	C+
SAT to CLT · Charlotte	1,376	86.6%	139 min	1.89%	A
SAT to MCO · Orlando	1,100	77.4%	73 min	1.73%	B
SAT to SLC · Salt Lake City	1,008	86.6%	70 min	0.89%	A+
SAT to DTW · Detroit	951	90.2%	75 min	0.74%	A+
SAT to BNA · Nashville	950	79.3%	55 min	0.53%	B+
SAT to MSP · Minneapolis	892	85.2%	72 min	1.35%	A
SAT to ELP · El Paso	765	79.8%	56 min	0.13%	B+
SAT to BWI · Baltimore	736	80.9%	55 min	1.63%	B
SAT to MDW · Chicago	673	78.2%	44 min	1.04%	B
SAT to IAD · Washington	641	93.7%	80 min	0.62%	A+
SAT to SAN · San Diego	610	78.7%	54 min	0.33%	B+
SAT to SEA · Seattle	558	77.0%	56 min	1.43%	B
SAT to EWR · Newark	554	86.7%	78 min	0.72%	A+
SAT to STL · St. Louis	547	85.7%	52 min	0.00%	A+
SAT to MIA · Miami	509	87.4%	89 min	1.18%	A

Departure window

The best time of day to leave SAT

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am11,704 flights91.9%
8am–11am5,258 flights88.1%
11am–2pm7,733 flights82.1%
2pm–5pm7,704 flights74.9%
5pm–8pm6,451 flights70.0%
8pm–5am1,604 flights65.8%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 91.9% of the time, against 65.8% for the overnight window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 11,704 flights scheduled in it.

Across the year

When SAT runs late

SAT's year swings by 13 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

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

June is the worst month at 73.5% on time, 13 points below February, 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 3,699 flights.

Across the week, Tuesday is the strongest day at 86.0% on time and Sunday the weakest at 78.6%. 7 points is a smaller lever than departure hour, but it is free.

Delay causes

Why SAT gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 42% of the 539,000 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.

Late-arriving aircraft
42%
Carrier
29%
National Airspace System
21%
Extreme weather
8%
Security
0%

42% 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 539,000 reported delay minutes here, that single category outweighs weather by 6 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 539,343 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.9% on time here.

Cancellations sit at 1.28% against a national 1.81%, which is ordinary. Diversions add another 0.31%.

6.3% 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 a little over an hour kind, which a normal layover absorbs.

40,454 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.

What to do with this

Flying out of SAT

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 86.3% on time and June 73.5%, a swing of 13 points. If the dates move at all, move them out of June before you think about anything else. 39,814 completed flights over 12 months sit behind that.

Common questions

SAT delay questions

How often is San Antonio (SAT) delayed?

Roughly 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 18.2% of the 40,454 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on San Antonio (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 San Antonio (SAT)?

The 5am–8am departure window is the strongest at 91.9% on time. The 8pm–5am window is the weakest at 65.8%, 26 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 San Antonio (SAT)?

June is the weakest month at 73.5% on time, compared with 86.3% in February. Across the year that is 13 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

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.

Key figures