Carrier route record

DLSAT→ATL

Delta Air Lines · San Antonio to Atlanta

Flights: 2,609
Period: July 2025 to June 2026
Share of route: 86%
Carriers: 4

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

Delta on SAT to ATL earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 2,609 flights, with a median arrival 10 minutes early.

Set against the rest of the country, Delta's SAT to ATL record is 10 points better than the US average of 77.6%. That gap is worth roughly 102 fewer late arrivals for every thousand flights.

On time

87.8%

Arrivals under 15 minutes late, of 2,552 completed flights

Avg delay

75 min

Across delayed arrivals only, not all flights

Cancelled

1.76%

National rate is 1.81%

Whole route

86.1%

Every carrier on SAT to ATL, 3,026 flights

These figures cover 2,609 flights between July 2025 and June 2026. The median arrival is 10 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

Delta against every carrier on SAT to ATL

Delta flew 2,609 of the 3,026 flights on SAT to ATL, most of the route. Its 87.8% on time is 2 points better than the route as a whole, which runs 86.1%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from Delta at 87.8% to Frontier at 62.2%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on SAT to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)	2,609	87.8%	75 min	1.76%	A
Southwest Airlinesthin sample	318	79.9%	46 min	0.31%	B+
Spirit Airlinesthin sample	8	75.0%	31 min	0.00%	B+
Frontier Airlinesthin sample	91	62.2%	99 min	0.00%	D+

Flight by flight

Delta flight numbers on SAT to ATL

Departure window

When Delta runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am751 flights93.5%
8am–11am501 flights91.9%
11am–2pm574 flights84.6%
2pm–5pm396 flights78.4%
5pm–8pm387 flights85.5%
8pm–5am—

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 93.5% of the time, against 78.4% for the afternoon window. That is 15 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 751 flights scheduled in it.

Across the year

Delta on SAT to ATL through the year

Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 78.1% on time, 18 points below September, the best at 95.9%. 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. May was the busiest month here, with 233 flights.

Across the week, Wednesday is the strongest day at 92.4% on time and Sunday the weakest at 83.6%. 9 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Carrier accounts for 42% of the 23,000 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.

Carrier
42%
Late-arriving aircraft
37%
National Airspace System
18%
Extreme weather
3%

37% 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 23,000 reported delay minutes here, that single category outweighs weather by 12 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 23,412 reported delay minutes.

The largest share of delay minutes, 42%, 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 9,854 of the 23,000 delay minutes reported here.

Cancellations sit at 1.76% against a national 1.81%, which is ordinary. Diversions add another 0.42%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.2% 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 874 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 81.5% on time across 2,610 flights, 6 points below 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 6 points of difference.

The sample behind these figures is 2,609 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking Delta on SAT to ATL

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 95.9% on time and July 78.1%, a swing of 18 points. If the dates move at all, move them out of July before you think about anything else. 2,552 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