Carrier route record
UASFO→PHX
United Airlines · San Francisco to Phoenix
- Flights
- 1,443
- Period
- July 2025 to June 2026
- Share of route
- 31%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on SFO to PHX lands a B+, 3 points 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 about an hour on average. That is a workable record, not a spotless one. That rests on 1,443 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 538 at 87.3% on time.
SkyWest Airlines is the most reliable of the three carriers covered here at 87.3% on time across 538 flights.
Key figures
On time
81.0%
Arrivals under 15 minutes late, of 1,429 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
0.49%
National rate is 1.81%
Whole route
74.4%
Every carrier on SFO to PHX, 4,643 flights
These figures cover 1,443 flights between July 2025 and June 2026. The median arrival is 5 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
United against every carrier on SFO to PHX
United flew 1,443 of the 4,643 flights on SFO to PHX, about 31% of it. Its 81.0% on time is 7 points better than the route as a whole, which runs 74.4%. Ranked by on-time rate it is number two of five carriers on the route, where the range runs from SkyWest at 87.3% to Frontier at 59.6%. One 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 87.3% of the time; Southwest Airlines manages 61.1%. 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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 538 | 87.3% | 67 min | 0.74% | A+ |
| United Airlines (this page) | 1,443 | 81.0% | 59 min | 0.49% | B+ |
| American Airlines | 1,320 | 75.7% | 106 min | 0.83% | B+ |
| Southwest Airlines | 1,079 | 61.1% | 57 min | 0.56% | D+ |
| Frontier Airlinesthin sample | 263 | 59.6% | 98 min | 3.04% | D− |
The spread between SkyWest and Southwest is 26 points, wide enough that it should decide the booking. On a hundred trips that is 26 more arrivals inside the on-time window.
Flight by flight
United flight numbers on SFO to PHX
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 13 points, against 26 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am124 flights90.9%
- 8am–11am253 flights79.8%
- 11am–2pm286 flights79.4%
- 2pm–5pm344 flights77.8%
- 5pm–8pm307 flights82.2%
- 8pm–5am129 flights82.9%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.9% of the time, against 77.8% for the afternoon window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 344 flights scheduled in it.
Across the year
United on SFO to PHX through the year
Delays peak in November, when the on-time rate falls to 68.5%. March is the strongest month at 92.1%. Moving a flexible trip across that boundary buys 24 points. December was the busiest month here, with 153 flights.
Across the week, Saturday is the strongest day at 86.2% on time and Monday the weakest at 77.8%. 8 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. Late-arriving aircraft accounts for 46% of the 16,000 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.
- 46%Late-arriving aircraft
- 30%Carrier
- 23%National Airspace System
- 1%Extreme weather
46% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 16,000 reported delay minutes here, that single category outweighs weather by 46 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 15,980 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 90.9% on time here.
Cancellations are rare at 0.49%, 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
5.5% 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 about an hour, which a normal layover absorbs.
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 73.1% on time across 1,444 flights, 8 points below 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 1,443 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 SFO to PHX
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 92.1% on time and November 68.5%, a swing of 24 points. If the dates move at all, move them out of November before you think about anything else. 1,429 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to PHX, every carrier
- United on PHX to SFO, the return leg
- SkyWest Airlines on SFO to PHX87.3%
- American Airlines on SFO to PHX75.7%
- Southwest Airlines on SFO to PHX61.1%
- Frontier Airlines on SFO to PHX59.6%
- United Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
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.