Carrier route record
UAPHL→SFO
United Airlines · Philadelphia to San Francisco
- Flights
- 707
- Period
- July 2025 to June 2026
- Share of route
- 35%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on PHL to SFO sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 707 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.6%, so United on PHL to SFO runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.
Key figures
On time
72.7%
Arrivals under 15 minutes late, of 703 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
0.57%
National rate is 1.81%
Whole route
73.3%
Every carrier on PHL to SFO, 1,995 flights
These figures cover 707 flights between July 2025 and June 2026. Beyond the headline rate, 9.8% 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 PHL to SFO
United flew 707 of the 1,995 flights on PHL to SFO, about 35% of it. Its 72.7% on time is about level with the route as a whole at 73.3%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from American at 73.7% to United at 72.7%.
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 |
|---|---|---|---|---|---|
| American Airlines | 1,288 | 73.7% | 74 min | 1.71% | C |
| United Airlines (this page) | 707 | 72.7% | 75 min | 0.57% | C+ |
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 24 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–8am276 flights83.7%
- 8am–11am159 flights75.6%
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm272 flights59.8%
- 8pm–5am—
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 59.8% on time, against 83.7% 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 276 flights scheduled in it.
Across the year
United on PHL to SFO through the year
June is the worst month at 53.7% on time, 35 points below September, 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. May was the busiest month here, with 83 flights.
Across the week, Saturday is the strongest day at 84.1% on time and Thursday the weakest at 67.3%. 17 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 56% of the 14,000 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.
- 56%National Airspace System
- 17%Late-arriving aircraft
- 14%Extreme weather
- 13%Carrier
Extreme weather accounts for 14% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.2 times the usual weather exposure. The split is drawn from 14,444 reported delay minutes.
56% 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 8,042 minutes out of 14,000, against a national NAS share of 21%.
Cancellations are rare at 0.57%, 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. 9.8% 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.
At 2,522 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 86.6% on time across 706 flights, 14 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 14 points of difference.
One caution: this is a thin sample. 707 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 PHL to SFO
Put together: treat all of this as provisional. 707 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 72.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 703 completed flights over 12 months sit behind that.
Related
Where to go next
- PHL to SFO, every carrier
- United on SFO to PHL, the return leg
- American Airlines on PHL to SFO73.7%
- United Airlines network-wide record
- Philadelphia International (PHL) 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.