Carrier route record
UAPHX→SFO
United Airlines · Phoenix to San Francisco
- Flights
- 1,444
- Period
- July 2025 to June 2026
- Share of route
- 31%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on PHX to SFO sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,444 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 538 at 68.5% on time.
The national on-time rate over the same period is 77.6%, so United on PHX to SFO runs 5 points behind the country as a whole. Across a thousand flights that is about 45 extra late arrivals.
Key figures
On time
73.1%
Arrivals under 15 minutes late, of 1,436 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.81%
Whole route
67.6%
Every carrier on PHX to SFO, 4,644 flights
These figures cover 1,444 flights between July 2025 and June 2026. Beyond the headline rate, 9.1% 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 PHX to SFO
United flew 1,444 of the 4,644 flights on PHX to SFO, about 31% of it. Its 73.1% on time is 6 points better than the route as a whole, which runs 67.6%. 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 60.5%. 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 68.5% of the time; Southwest Airlines manages 60.5%. Sample sizes sit next to every figure, because a two-point gap across 1,079 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) | 1,444 | 73.1% | 62 min | 0.55% | C+ |
| Frontier Airlinesthin sample | 263 | 68.6% | 61 min | 0.76% | C+ |
| SkyWest Airlines | 538 | 68.5% | 65 min | 0.19% | C+ |
| American Airlines | 1,319 | 66.9% | 76 min | 0.91% | C+ |
| Southwest Airlines | 1,079 | 60.5% | 55 min | 0.28% | D+ |
SkyWest leads Southwest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 22 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am371 flights81.9%
- 8am–11am265 flights75.5%
- 11am–2pm238 flights65.0%
- 2pm–5pm238 flights81.9%
- 5pm–8pm314 flights59.5%
- 8pm–5am18 flights—
Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 59.5% on time, against 81.9% 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 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 82.4% on time and Monday the weakest at 64.1%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. National Airspace System accounts for 57% of the 24,000 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.
- 57%National Airspace System
- 25%Late-arriving aircraft
- 18%Carrier
- 0%Extreme weather
57% 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 14,000 minutes out of 24,000, against a national NAS share of 21%. The split is drawn from 23,960 reported delay minutes.
Cancellations are rare at 0.55%, 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.1% 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.
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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 81.0% on time across 1,443 flights, 8 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 8 points of difference.
The sample behind these figures is 1,444 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. 1,436 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 SFO68.6%
- SkyWest Airlines on PHX to SFO68.5%
- American Airlines on PHX to SFO66.9%
- Southwest Airlines on PHX to SFO60.5%
- 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 7.04 million flight records
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.