San Antonio, TX · departure reliability

SAT

San Antonio International

Departures: 40,731
Period: June 2025 to May 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, 5 points better than the national rate of 77.4%. About one flight in six 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 40,731 flights, of which Delta Air Lines flew 6,851 at 85.3% on time.

Delta Air Lines is the most reliable of the nine carriers covered here at 85.3% on time across 6,851 flights.

On time

81.9%

Departures arriving under 15 minutes late at their destination

Avg delay

75 min

Across delayed flights only

Cancelled

1.26%

National rate is 1.80%

Best carrier

Delta

85.3% on time here

These figures cover 41,000 flights between June 2025 and May 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 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.

On-time performance by carrier departing SAT
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	15,433	81.4%	54 min	0.54%	B+
American Airlines	7,508	80.8%	107 min	2.45%	B
Delta Air Lines	6,851	85.3%	79 min	1.42%	A
United Airlines	5,684	83.4%	76 min	0.83%	B+
SkyWest Airlines	1,631	83.8%	110 min	1.35%	B
Spirit Airlines	1,205	79.5%	81 min	2.82%	B
Frontier Airlines	879	77.2%	92 min	1.25%	B
Envoy Air	878	73.8%	72 min	2.62%	C
Alaska Airlines	558	74.9%	53 min	1.43%	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

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 81.9%.

Busiest routes from SAT by flight volume
Route	Flights	On time	Avg delay	Cancelled	Grade
SAT to DFW · Dallas-Fort Worth	4,401	77.2%	103 min	3.32%	B−
SAT to ATL · Atlanta	3,078	84.7%	74 min	1.56%	B
SAT to DEN · Denver	3,013	81.1%	73 min	0.46%	B+
SAT to DAL · Dallas	2,717	83.8%	60 min	1.18%	B
SAT to PHX · Phoenix	2,502	83.1%	80 min	0.56%	B+
SAT to IAH · Houston	2,451	81.4%	70 min	0.98%	B+
SAT to LAS · Las Vegas	2,079	83.1%	60 min	0.48%	B+
SAT to ORD · Chicago	1,963	76.4%	72 min	2.04%	B
SAT to LAX · Los Angeles	1,921	87.2%	77 min	0.42%	A+
SAT to HOU · Houston	1,409	74.1%	49 min	0.35%	C+
SAT to CLT · Charlotte	1,371	86.3%	129 min	1.82%	A
SAT to MCO · Orlando	1,142	77.2%	72 min	1.66%	B
SAT to SLC · Salt Lake City	1,008	86.3%	77 min	0.99%	A+
SAT to DTW · Detroit	961	89.9%	81 min	0.73%	A+
SAT to BNA · Nashville	953	80.7%	54 min	0.73%	B+
SAT to MSP · Minneapolis	893	84.1%	79 min	1.23%	B
SAT to ELP · El Paso	781	80.1%	62 min	0.00%	B+
SAT to BWI · Baltimore	748	81.2%	55 min	1.87%	B
SAT to MDW · Chicago	685	80.6%	43 min	0.88%	B+
SAT to IAD · Washington	636	93.1%	89 min	0.63%	A+
SAT to SAN · San Diego	609	78.6%	53 min	0.33%	B+
SAT to SEA · Seattle	558	74.9%	53 min	1.43%	C
SAT to STL · St. Louis	547	87.2%	56 min	0.00%	A+
SAT to EWR · Newark	541	86.9%	76 min	0.92%	A+
SAT to MIA · Miami	483	87.9%	87 min	1.45%	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–8am11,670 flights92.2%
8am–11am5,382 flights88.1%
11am–2pm7,826 flights82.2%
2pm–5pm7,731 flights75.2%
5pm–8pm6,495 flights69.6%
8pm–5am1,627 flights66.4%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 92.2% of the time, against 66.4% 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.

Across the year

When SAT runs late

Twelve months, one bar each, drawn from the same 40,731 flights. The strip shows how much of SAT's record is set by the calendar rather than by the operation.

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

June is the worst month at 75.5% on time, 11 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.

Across the week, Tuesday is the strongest day at 85.3% on time and Sunday the weakest at 78.5%. 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 543,000 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
22%
Extreme weather
7%
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 543,000 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 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 92.2% on time here.

Cancellations sit at 1.26% against a national 1.80%, which is ordinary. Diversions add another 0.31%.

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

40,731 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: avoid the 8pm–5am departure. It runs 66.4% on time against 92.2% for the 5am–8am slot, and that 26 points is the largest single thing you control here. Delta Air Lines is the strongest operator if the fares are close.

Common questions

SAT delay questions

How often is San Antonio (SAT) delayed?

About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.1% of the 40,731 flights in this analysis, against 22.6% 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 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 San Antonio (SAT)?

The 5am–8am departure window is the strongest at 92.2% on time. The 8pm–5am window is the weakest at 66.4%, 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 75.5% on time, compared with 86.3% in February. Across the year that is 11 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, June 2025 to May 2026. Updated monthly. How this data is collected.

Key figures