Route reliability record

SFO→AUS

San Francisco to Austin

Flights: 2,792
Period: July 2025 to June 2026
Distance: 1,504 mi
Carriers: 5

This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 2,792 flights, of which United Airlines flew 1,653 at 82.7% on time.

The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

74.8%

Arrivals under 15 minutes late, of 2,759 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

0.79%

National rate is 1.81%

Best carrier

United

82.7% on time across 1,653 flights

These figures cover 2,792 flights between July 2025 and June 2026. Beyond the headline rate, 8.6% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Which airline is most reliable on SFO to AUS

The choice of carrier is not cosmetic here. United Airlines arrives on time 82.7% of the time; Delta Air Lines manages 61.0%. Sample sizes sit next to every figure, because a two-point gap across 444 flights means less than a ten-point one.

On-time performance by carrier on SFO to AUS
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	8	100.0%	—	0.00%	A+
Alaska Airlinesthin sample	343	84.9%	59 min	0.87%	B+
United Airlines	1,653	82.7%	52 min	0.73%	B+
Delta Air Lines	444	61.0%	73 min	1.58%	D
Southwest Airlinesthin sample	344	44.8%	64 min	0.00%	F+

The spread between United and Delta is 22 points, wide enough that it should decide the booking. On a hundred trips that is 22 more arrivals inside the on-time window.

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 31 points, against 22 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am457 flights95.8%
8am–11am273 flights72.5%
11am–2pm1,018 flights65.3%
2pm–5pm279 flights68.8%
5pm–8pm591 flights75.8%
8pm–5am174 flights85.5%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 65.3% on time against 95.8% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 1,018 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 23 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.August best, June worst

June is the worst month at 61.4% on time, 23 points below August, the best at 84.1%. 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. December was the busiest month here, with 260 flights.

Across the week, Saturday is the strongest day at 81.2% on time and Sunday the weakest at 71.4%. 10 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 55% of the 42,000 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
55%
Carrier
27%
National Airspace System
17%
Extreme weather
0%

55% 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 42,000 reported delay minutes here, that single category outweighs weather by 55 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 42,332 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 95.8% on time here.

Cancellations are rare at 0.79%, 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.

Connections and stage length

What a delay here actually costs

8.6% 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 about an hour kind, which a normal layover absorbs.

At 1,504 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg runs 74.9% on time across 2,795 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 2,792 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 this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 84.1% on time and June 61.4%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 2,759 completed flights over 12 months sit behind that.

Common questions

SFO to AUS questions

How often is SFO to AUS delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.2% of the 2,792 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on SFO to AUS?

United Airlines leads at 82.7% on time across 1,653 flights. Delta Air Lines is at the other end on 61.0%, a gap of 22 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 SFO to AUS?

The 5am–8am departure window is the strongest at 95.8% on time. The 11am–2pm window is the weakest at 65.3%, 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 SFO to AUS?

June is the weakest month at 61.4% on time, compared with 84.1% in August. Across the year that is 23 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

Direction matters. SFO to AUS and AUS to SFO are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

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