Route reliability record
PHL→SFO
Philadelphia to San Francisco
- Flights
- 2,085
- Period
- September 2025 to August 2026
- Distance
- 2,522 mi
- Carriers
- 2
This route 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 77.3%. The late ones land a little over an hour behind schedule. That rests on 2,085 PHL to SFO flights, of which American Airlines flew 1,335 at 73.2% on time.
Best time to fly PHL to SFO: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 85.3% of the time and Wednesday flights 78.8%, against 71.9% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 54 extra late arrivals.
Key figures
On time
71.9%
Arrivals under 15 minutes late, of 2,056 completed flights
Avg delay
80 min
Across delayed arrivals only, not all flights
Cancelled
1.25%
National rate is 1.89%
Best carrier
American
73.2% on time across 1,335 flights
These figures cover 2,085 flights between September 2025 and August 2026. Beyond the headline rate, 11.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on PHL to SFO
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines | 1,335 | 73.2% | 80 min | 1.65% | C |
| United Airlines | 750 | 69.7% | 81 min | 0.53% | C+ |
No carrier stands out. American tops the table at 73.2%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on PHL to SFO
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Philadelphia to San Francisco
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. PHL → SFOPhiladelphia to San Francisco | American Airlines | 72.0% | 73.2% | 1.65% | 5am–8am, Tue | — |
| 2. PHL → SFOPhiladelphia to San Francisco | United Airlines | 69.3% | 69.7% | 0.53% | 5am–8am, Sat | UA 1575 18:25 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 points, against 4 points between the best and worst carrier.
- 5am–8am327 flights85.3%
- 8am–11am578 flights76.5%
- 11am–2pm—
- 2pm–5pm363 flights74.2%
- 5pm–8pm710 flights60.2%
- 8pm–5am107 flights76.5%
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 60.2% on time, against 85.3% 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 5pm–8pm window is the busiest, with 710 flights scheduled in it.
Explore
Filter PHL to SFO by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On PHL to SFO, the best departure window is 5am–8am at 85.3% on time and the worst is 5pm–8pm at 60.2%, a wide gap of 25.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am85.3%
- 8–11am76.5%
- 11am–2pm—
- 2–5pm74.2%
- 5–8pm60.2%
- 8pm–5am76.5%
best all US flightsScale 50% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 30 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 57.5% on time, 30 points below September, the best at 87.3%. 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. July was the busiest month here, with 234 flights.
Across the week, Wednesday is the strongest day at 78.8% on time and Thursday the weakest at 61.6%, a spread of 17 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 44% of the 46,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%National Airspace System
- 23%Carrier
- 21%Late-arriving aircraft
- 13%Extreme weather
- 0%Security
Extreme weather accounts for 13% 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 2.1 times the usual weather exposure. The split is drawn from 46,229 reported delay minutes.
44% 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 20,000 minutes out of 46,000, against a national NAS share of 21%.
Cancellations sit at 1.25% against a national 1.89%, which is ordinary. Diversions add another 0.14%.
Connections and stage length
What a delay here actually costs
11.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 85.2% on time across 2,082 flights, 13 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 13 points of difference.
The sample behind these figures is 2,085 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.
Work out the risk of missing a connection in SFO after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 87.3% on time and June 57.5%, a swing of 30 points. If the dates move at all, move them out of June before you think about anything else. 2,056 completed flights over 12 months sit behind that.
Common questions
PHL to SFO questions
How often is PHL to SFO delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 28.1% of the 2,085 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on PHL to SFO?
American Airlines leads at 73.2% on time across 1,335 flights. United Airlines is at the other end on 69.7%, a gap of 4 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on PHL to SFO?
The 5am–8am departure window is the strongest at 85.3% on time. The 5pm–8pm window is the weakest at 60.2%, 25 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on PHL to SFO?
June is the weakest month at 57.5% on time, compared with 87.3% in September. Across the year that is 30 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- SFO to PHL — the return legseparate record
- Philadelphia International (PHL) delay statistics
- San Francisco International (SFO) delay statistics
- American Airlines on PHL to SFO73.2%
- United Airlines on PHL to SFO69.7%
- PHL to ATL, a related route78.0%
- LAX to SFO, a related route60.1%
- PHL to MCO, a related route72.4%
- American Airlines on-time record73.2%
- United Airlines on-time record69.7%
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.05 million flight records
Direction matters. PHL to SFO and SFO to PHL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.