Carrier route record
UAATL→SFO
United Airlines · Atlanta to San Francisco
- Flights
- 636
- Period
- September 2025 to August 2026
- Share of route
- 19%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on ATL to SFO lands a B+, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 636 flights, with a median arrival 4 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate United on ATL 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
76.9%
Arrivals under 15 minutes late, of 633 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
0.47%
National rate is 1.89%
Whole route
69.9%
Every carrier on ATL to SFO, 3,339 flights
These figures cover 636 flights between September 2025 and August 2026. Beyond the headline rate, 9.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
United against every carrier on ATL to SFO
United flew 636 of the 3,339 flights on ATL to SFO, about 19% of it. Its 76.9% on time is 7 points better than the route as a whole, which runs 69.9%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 76.9% to Frontier at 65.6%. One 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 636 | 76.9% | 69 min | 0.47% | B+ |
| Delta Air Lines | 2,393 | 68.5% | 55 min | 0.67% | C+ |
| Frontier Airlinesthin sample | 310 | 65.6% | 63 min | 1.29% | C |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 17 points, against half a point between the best and worst carrier.
- 5am–8am342 flights85.0%
- 8am–11am23 flights—
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm268 flights67.8%
- 8pm–5am3 flights—
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 85.0% of the time, against 67.8% for the evening window. That is 17 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 342 flights scheduled in it.
Across the year
United on ATL to SFO through the year
June is the worst month at 59.6% on time, 35 points below March, the best at 94.3%. 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. November was the busiest month here, with 62 flights.
Across the week, Wednesday is the strongest day at 82.4% on time and Sunday the weakest at 69.7%, a spread of 13 points.
Arrival by arrival
How late United on ATL to SFO runs when it is late
United on ATL to SFO often beats the schedule: 189 of 633 completed flights, 30%, arrived 15 minutes or more early. The 146 late arrivals split 51 under half an hour, 34 between 30 and 60 minutes, and 61 an hour or more.
- 15+ min early189 flights29.9%
- Within 15 min298 flights47.1%
- 15–29 min late51 flights8.1%
- 30–59 min late34 flights5.4%
- 1–2 hours late34 flights5.4%
- 2+ hours late27 flights4.3%
Scale runs 0% to 100%.
Share of 633 completed flights by arrival against schedule.
28 of 145 late departures made up the time and arrived on time, 19% of them. 29 flights left on time and still arrived late.
The worst days
Worst days for United on ATL to SFO
The latest arrival of the period was on 28 December 2025, 5 hours 42 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across December, August, March, July and January, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 28 December 2025 | 5 hours 42 minutes | Carrier |
| 23 August 2026 | 4 hours 50 minutes | Carrier |
| 15 March 2026 | 3 hours 41 minutes | National Airspace System |
| 2 July 2026 | 3 hours 39 minutes | Late-arriving aircraft |
| 5 January 2026 | 3 hours 33 minutes | National Airspace System |
Delay causes
Why United runs late on this route
National Airspace System accounts for 59% of the 10,000 delay minutes carriers reported here, and the remaining four split what is left.
- 59%National Airspace System
- 24%Carrier
- 16%Late-arriving aircraft
- 1%Extreme weather
59% 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 5,963 minutes out of 10,000, against a national NAS share of 21%. The split is drawn from 10,023 reported delay minutes.
Cancellations are rare at 0.47%, below the national 1.89% 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
9.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 2,139 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 85.9% on time across 636 flights, 9 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 9 points of difference.
One caution: this is a thin sample. 636 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking United on ATL to SFO
Put together: treat all of this as provisional. 636 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 76.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 633 completed flights over 12 months sit behind that.
Related
Where to go next
- ATL to SFO, every carrier
- United on SFO to ATL, the return leg
- Delta Air Lines on ATL to SFO68.5%
- Frontier Airlines on ATL to SFO65.6%
- United Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- San Francisco International (SFO) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- How often a connection fails at the major US hubs
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.