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DelayAtlas

Carrier route record

UAAUSSFO

United Airlines · Austin to San Francisco

Flights
1,655
Period
July 2025 to June 2026
Share of route
59%
Carriers
5
B+GRADE

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

United on AUS to SFO lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 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 1,655 flights, with a median arrival 9 minutes early.

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

Key figures

On time

78.8%

Arrivals under 15 minutes late, of 1,640 completed flights

Avg delay

74 min

Across delayed arrivals only, not all flights

Cancelled

0.79%

National rate is 1.81%

Whole route

74.9%

Every carrier on AUS to SFO, 2,795 flights

These figures cover 1,655 flights between July 2025 and June 2026. Beyond the headline rate, 8.7% 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

United against every carrier on AUS to SFO

United flew 1,655 of the 2,795 flights on AUS to SFO, most of the route. Its 78.8% on time is 4 points better than the route as a whole, which runs 74.9%. Ranked by on-time rate it is first of five carriers on the route, where the range runs from United at 78.8% to Southwest at 62.6%. 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 AUS to SFO
AirlineFlightsOn timeAvg delayCancelledGrade
United Airlines (this page)1,65578.8%74 min0.79%B+
Alaska Airlinesthin sample34478.8%60 min1.16%B
SkyWest Airlinesthin sample875.0%17 min0.00%B+
Delta Air Lines44466.7%59 min1.13%C
Southwest Airlinesthin sample34462.6%51 min0.58%D+

Flight by flight

United flight numbers on AUS to SFO

Departure window

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 50 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–8am429 flights93.4%
  • 8am–11am361 flights77.4%
  • 11am–2pm268 flights76.2%
  • 2pm–5pm255 flights76.9%
  • 5pm–8pm243 flights74.3%
  • 8pm–5am99 flights43.9%

Scale runs 35% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 43.9% on time, against 93.4% 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 5am–8am window is the busiest, with 429 flights scheduled in it.

Across the year

United on AUS to SFO through the year

On-time rate by calendar month83J83F87M66A52M57J79J92A93S88O85N88D
Darker means more delays. Figures are on-time percentages.September best, May worst

September is the best month on the calendar at 93.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. May was the busiest month here, with 159 flights.

Across the week, Saturday is the strongest day at 89.3% on time and Sunday the weakest at 73.6%. 16 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week74.5Mon85.5Tue78.4Wed75.6Thu77.3Fri89.3Sat73.6Sun
Monday: 74.5 percent on time. Tuesday: 85.5 percent on time. Wednesday: 78.4 percent on time. Thursday: 75.6 percent on time. Friday: 77.3 percent on time. Saturday: 89.3 percent on time. Sunday: 73.6 percent on time

Delay causes

Why United runs late on this route

One category carries most of the weight here. National Airspace System accounts for 49% of the 26,000 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
    49%
  • Late-arriving aircraft
    30%
  • Carrier
    20%
  • Extreme weather
    2%

49% 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 12,000 minutes out of 26,000, against a national NAS share of 21%. The split is drawn from 25,622 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 93.4% 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 costs

8.7% 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 last a little over an hour, 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 is a different operation and performs like one: it runs 82.7% on time across 1,653 flights, 4 points above 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 4 points of difference.

The sample behind these figures is 1,655 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 United on AUS to SFO

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 93.3% on time and May 51.6%, a swing of 42 points. If the dates move at all, move them out of May before you think about anything else. 1,640 completed flights over 12 months sit behind that.

Related

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.