Carrier route record
UASFO→PHL
United Airlines · San Francisco to Philadelphia
- Flights
- 706
- 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 SFO to PHL earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 50 minutes. That rests on 706 flights, with a median arrival 9 minutes early.
Set against the rest of the country, United's SFO to PHL record is 9 points better than the US average of 77.6%. That gap is worth roughly 90 fewer late arrivals for every thousand flights.
Key figures
On time
86.6%
Arrivals under 15 minutes late, of 702 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.57%
National rate is 1.81%
Whole route
85.4%
Every carrier on SFO to PHL, 1,992 flights
These figures cover 706 flights between July 2025 and June 2026. The median arrival is 9 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 PHL
United flew 706 of the 1,992 flights on SFO to PHL, about 35% of it. Its 86.6% on time is about level with the route as a whole at 85.4%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 86.6% to American at 84.7%.
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 |
|---|---|---|---|---|---|
| United Airlines (this page) | 706 | 86.6% | 50 min | 0.57% | A+ |
| American Airlines | 1,286 | 84.7% | 108 min | 1.87% | B |
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 12 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–8am—
- 8am–11am269 flights88.5%
- 11am–2pm109 flights84.0%
- 2pm–5pm30 flights76.7%
- 5pm–8pm—
- 8pm–5am298 flights86.9%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 88.5% of the time, against 76.7% for the afternoon window. That is 12 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
Delays peak in May, when the on-time rate falls to 75.9%. February is the strongest month at 94.9%. Moving a flexible trip across that boundary buys 19 points. May was the busiest month here, with 83 flights.
Across the week, Tuesday is the strongest day at 91.8% on time and Thursday the weakest at 81.5%. 10 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 43% of the 4,658 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.
- 43%Late-arriving aircraft
- 28%National Airspace System
- 26%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. That is a cascade, and cascades start small and grow through the day. Across 4,658 reported delay minutes here, that single category outweighs weather by 20 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 4,658 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 88.5% on time here.
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
Badly late arrivals are rare here: only 3.7% land an hour or more behind schedule, against 8.1% 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 72.7% on time across 707 flights, 14 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 14 points of difference.
One caution: this is a thin sample. 706 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. 706 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 86.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 702 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 PHL84.7%
- 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 7.04 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.