Carrier route record
UAPHX→SFO
United Airlines · Phoenix to San Francisco
- Flights
- 1,489
- Period
- September 2025 to August 2026
- Share of route
- 31%
- Carriers
- 6
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on PHX to SFO draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 1,489 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 572 at 63.7% on time.
The national on-time rate over the same period is 77.3%, so United on PHX to SFO runs 10 points behind the country as a whole. Across a thousand flights that is about 96 extra late arrivals.
Key figures
On time
67.7%
Arrivals under 15 minutes late, of 1,482 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
0.47%
National rate is 1.89%
Whole route
63.6%
Every carrier on PHX to SFO, 4,728 flights
These figures cover 1,489 flights between September 2025 and August 2026. Beyond the headline rate, 10.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
United against every carrier on PHX to SFO
United flew 1,489 of the 4,728 flights on PHX to SFO, about 31% of it. Its 67.7% on time is 4 points better than the route as a whole, which runs 63.6%. Ranked by on-time rate it is number two of six carriers on the route, where the range runs from Envoy at 100.0% to Southwest at 57.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 63.7% of the time; Southwest Airlines manages 57.7%. Sample sizes sit next to every figure, because a two-point gap across 1,076 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 1 | 100.0% | — | 0.00% | A+ |
| United Airlines (this page) | 1,489 | 67.7% | 59 min | 0.47% | C+ |
| Frontier Airlinesthin sample | 278 | 65.8% | 64 min | 1.08% | C |
| SkyWest Airlines | 572 | 63.7% | 67 min | 0.17% | D+ |
| American Airlines | 1,312 | 63.2% | 77 min | 0.91% | D+ |
| Southwest Airlines | 1,076 | 57.7% | 56 min | 0.37% | D+ |
SkyWest leads Southwest by 6 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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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 29 points, against 6 points between the best and worst carrier.
- 5am–8am371 flights75.5%
- 8am–11am327 flights67.6%
- 11am–2pm241 flights60.1%
- 2pm–5pm225 flights82.1%
- 5pm–8pm307 flights53.0%
- 8pm–5am18 flights—
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 53.0% on time, against 82.1% for the 2pm–5pm 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 371 flights scheduled in it.
Across the year
United on PHX to SFO through the year
June is the worst month at 37.1% on time, 51 points below March, the best at 88.5%. 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 152 flights.
Across the week, Tuesday is the strongest day at 78.5% on time and Monday the weakest at 55.9%, a spread of 23 points.
Arrival by arrival
How late United on PHX to SFO runs when it is late
The 478 late arrivals split 148 under half an hour, 173 between 30 and 60 minutes, and 157 an hour or more.
- 15+ min early336 flights22.7%
- Within 15 min668 flights45.1%
- 15–29 min late148 flights10.0%
- 30–59 min late173 flights11.7%
- 1–2 hours late107 flights7.2%
- 2+ hours late50 flights3.4%
Scale runs 0% to 100%.
Share of 1,482 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 398 departures that left 15 minutes late or more, only 44 made it up before arrival. In the other direction, 124 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.
The worst days
Worst days for United on PHX to SFO
The latest arrival of the period was on 26 September 2025, 6 hours 24 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across September, January, July and August, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 26 September 2025 | 6 hours 24 minutes | Late-arriving aircraft |
| 5 September 2025 | 6 hours 8 minutes | Carrier |
| 5 January 2026 | 4 hours 28 minutes | National Airspace System |
| 13 July 2026 | 4 hours 23 minutes | Late-arriving aircraft |
| 9 August 2026 | 4 hours 7 minutes | National Airspace System |
Delay causes
Why United runs late on this route
National Airspace System accounts for 62% of the 28,000 delay minutes carriers reported here, and the remaining four split what is left.
- 62%National Airspace System
- 24%Late-arriving aircraft
- 14%Carrier
- 0%Extreme weather
62% 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 18,000 minutes out of 28,000, against a national NAS share of 21%. The split is drawn from 28,342 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
10.6% 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.
The 651 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.
The return leg is a different operation and performs like one: it runs 79.9% on time across 1,488 flights, 12 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 12 points of difference.
The sample behind these figures is 1,489 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 PHX to SFO
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 88.5% on time and June 37.1%, a swing of 51 points. If the dates move at all, move them out of June before you think about anything else. 1,482 completed flights over 12 months sit behind that.
Related
Where to go next
- PHX to SFO, every carrier
- United on SFO to PHX, the return leg
- Frontier Airlines on PHX to SFO65.8%
- SkyWest Airlines on PHX to SFO63.7%
- American Airlines on PHX to SFO63.2%
- Southwest Airlines on PHX to SFO57.7%
- United Airlines network-wide record
- Phoenix Sky Harbor International (PHX) delay statistics
- San Francisco International (SFO) delay statistics
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.05 million flight records
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.