Route reliability record

AUS→SFO

Austin to San Francisco

Flights: 2,795
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 2,795 flights, of which United Airlines flew 1,655 at 78.8% 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

74.9%

Arrivals under 15 minutes late, of 2,767 completed flights

Avg delay

65 min

Across delayed arrivals only, not all flights

Cancelled

0.86%

National rate is 1.81%

Best carrier

United

78.8% on time across 1,655 flights

These figures cover 2,795 flights between July 2025 and June 2026. Beyond the headline rate, 9.0% 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 AUS to SFO

The choice of carrier is not cosmetic here. United Airlines arrives on time 78.8% of the time; Delta Air Lines manages 66.7%. 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 AUS to SFO
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,655	78.8%	74 min	0.79%	B+
Alaska Airlinesthin sample	344	78.8%	60 min	1.16%	B
SkyWest Airlinesthin sample	8	75.0%	17 min	0.00%	B+
Delta Air Lines	444	66.7%	59 min	1.13%	C
Southwest Airlinesthin sample	344	62.6%	51 min	0.58%	D+

The spread between United and Delta is 12 points, wide enough that it should decide the booking. On a hundred trips that is 12 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 39 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am608 flights90.7%
8am–11am683 flights74.1%
11am–2pm558 flights72.1%
2pm–5pm542 flights68.0%
5pm–8pm256 flights73.2%
8pm–5am148 flights51.4%

Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 51.4% on time, against 90.7% 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 8am–11am window is the busiest, with 683 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 32 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, May worst

Delays peak in May, when the on-time rate falls to 53.2%. August is the strongest month at 85.5%. Moving a flexible trip across that boundary buys 32 points. December was the busiest month here, with 261 flights.

Across the week, Saturday is the strongest day at 83.3% on time and Sunday the weakest at 69.9%. 13 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. National Airspace System accounts for 45% of the 45,000 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.

National Airspace System
45%
Late-arriving aircraft
32%
Carrier
21%
Extreme weather
1%
Security
0%

45% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 20,000 minutes out of 45,000, against a national NAS share of 21%. The split is drawn from 45,145 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 90.7% on time here.

Cancellations are rare at 0.86%, 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.0% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

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 74.8% on time across 2,792 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 2,795 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 85.5% on time and May 53.2%, a swing of 32 points. If the dates move at all, move them out of May before you think about anything else. 2,767 completed flights over 12 months sit behind that.

Common questions

AUS to SFO questions

How often is AUS to SFO 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 25.1% of the 2,795 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on AUS to SFO?

United Airlines leads at 78.8% on time across 1,655 flights. Delta Air Lines is at the other end on 66.7%, 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 AUS to SFO?

The 5am–8am departure window is the strongest at 90.7% on time. The 8pm–5am window is the weakest at 51.4%, 39 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 May delays on AUS to SFO?

May is the weakest month at 53.2% on time, compared with 85.5% in August. Across the year that is 32 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. AUS to SFO and SFO to AUS 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