Carrier route record
UASFO→PHL
United Airlines · San Francisco to Philadelphia
- Flights
- 749
- Period
- September 2025 to August 2026
- Share of route
- 36%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SFO to PHL earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 50 minutes. That rests on 749 flights, with a median arrival 8 minutes early.
Set against the rest of the country, United's SFO to PHL record is 8 points better than the US average of 77.3%. That gap is worth roughly 75 fewer late arrivals for every thousand flights.
Key figures
On time
84.8%
Arrivals under 15 minutes late, of 743 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.53%
National rate is 1.89%
Whole route
85.2%
Every carrier on SFO to PHL, 2,082 flights
These figures cover 749 flights between September 2025 and August 2026. The median arrival is 8 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.
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Carrier by carrier
United against every carrier on SFO to PHL
United flew 749 of the 2,082 flights on SFO to PHL, about 36% of it. Its 84.8% on time is about level with the route as a whole at 85.2%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from American at 85.4% to United at 84.8%.
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 | 1,333 | 85.4% | 107 min | 1.80% | A |
| United Airlines (this page) | 749 | 84.8% | 49 min | 0.53% | B+ |
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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 26 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am269 flights91.4%
- 11am–2pm124 flights78.5%
- 2pm–5pm58 flights65.5%
- 5pm–8pm—
- 8pm–5am298 flights85.2%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 91.4% of the time, against 65.5% for the afternoon window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 298 flights scheduled in it.
Across the year
United on SFO to PHL through the year
August is the worst month at 69.6% on time, 25 points below February, the best at 94.9%. 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, Tuesday is the strongest day at 95.1% on time and Thursday the weakest at 78.4%, a spread of 17 points.
Arrival by arrival
How late United on SFO to PHL runs when it is late
United on SFO to PHL often beats the schedule: 251 of 743 completed flights, 34%, arrived 15 minutes or more early. The 113 late arrivals split 41 under half an hour, 45 between 30 and 60 minutes, and 27 an hour or more.
- 15+ min early251 flights33.8%
- Within 15 min379 flights51.0%
- 15–29 min late41 flights5.5%
- 30–59 min late45 flights6.1%
- 1–2 hours late21 flights2.8%
- 2+ hours late6 flights0.8%
Scale runs 0% to 100%.
Share of 743 completed flights by arrival against schedule.
A late pushback is often recovered here: of 130 departures that left 15 minutes late or more, 46 still arrived on time. 29 flights left on time and still arrived late.
The worst days
Worst days for United on SFO to PHL
The latest arrival of the period was on 15 February 2026, 6 hours 31 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across February, August, July and December, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 15 February 2026 | 6 hours 31 minutes | Carrier |
| 20 August 2026 | 3 hours 4 minutes | National Airspace System |
| 21 July 2026 | 2 hours 44 minutes | National Airspace System |
| 3 August 2026 | 2 hours 11 minutes | Late-arriving aircraft |
| 19 December 2025 | 2 hours 2 minutes | Carrier |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 43% of the 5,530 delay minutes carriers reported here, and the remaining four split what is left.
- 43%Late-arriving aircraft
- 31%National Airspace System
- 24%Carrier
- 2%Extreme weather
43% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,530 reported delay minutes here, that single category outweighs weather by 23 to one. The split is drawn from 5,530 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.4% on time here.
Cancellations are rare at 0.53%, 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
Badly late arrivals are rare here: only 3.6% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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 69.7% on time across 750 flights, 15 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 15 points of difference.
One caution: this is a thin sample. 749 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 SFO to PHL
Put together: treat all of this as provisional. 749 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 84.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 743 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to PHL, every carrier
- United on PHL to SFO, the return leg
- American Airlines on SFO to PHL85.4%
- United Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Philadelphia International (PHL) delay statistics
- Why the first flight of the morning is statistically safest
- 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.