Route reliability record
RDU→SFO
Raleigh to San Francisco
- Flights
- 884
- Period
- September 2025 to August 2026
- Distance
- 2,400 mi
- Carriers
- 1
This route lands a B+, about a point better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 884 RDU to SFO flights, with a median arrival 8 minutes early.
Best time to fly RDU to SFO: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 87.4% of the time and Tuesday flights 93.3%, against 78.1% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.1%
Arrivals under 15 minutes late, of 875 completed flights
Avg delay
67 min
Across delayed arrivals only, not all flights
Cancelled
0.45%
National rate is 1.89%
Best carrier
United
78.1% on time across 884 flights
These figures cover 884 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
Which airline is most reliable on RDU to SFO
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 | 884 | 78.1% | 67 min | 0.45% | B+ |
Flight by flight
Flights on RDU 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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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 21 points, against half a point between the best and worst carrier.
- 5am–8am272 flights87.4%
- 8am–11am276 flights78.7%
- 11am–2pm9 flights—
- 2pm–5pm50 flights84.0%
- 5pm–8pm277 flights66.4%
- 8pm–5am—
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 87.4% of the time, against 66.4% for the evening window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 277 flights scheduled in it.
Explore
Filter RDU 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 RDU to SFO, the best departure window is 5am–8am at 87.4% on time and the worst is 5pm–8pm at 66.4%, a wide gap of 21.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am87.4%
- 8–11am78.7%
- 11am–2pm—
- 2–5pm84.0%
- 5–8pm66.4%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 38 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 53.3% on time, 38 points below September, the best at 90.9%. 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. December was the busiest month here, with 88 flights.
Across the week, Tuesday is the strongest day at 93.3% on time and Thursday the weakest at 69.8%, a spread of 24 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 55% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 55%National Airspace System
- 24%Late-arriving aircraft
- 19%Carrier
- 1%Extreme weather
55% 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 7,072 minutes out of 13,000, against a national NAS share of 21%. The split is drawn from 12,803 reported delay minutes.
Cancellations are rare at 0.45%, 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 actually costs
7.5% of arrivals land an hour or more late, close to the national 8.3%, so 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.
At 2,400 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 90.1% on time across 885 flights, 12 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 12 points of difference.
One caution: this is a thin sample. 884 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.
Work out the risk of missing a connection in SFO after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 884 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 78.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 875 completed flights over 12 months sit behind that.
Common questions
RDU to SFO questions
How often is RDU to SFO delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.9% of the 884 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is RDU to SFO compared with the rest of the country?
78.1% of flights arrive on time here against a national 77.3%, a difference of about a point in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on RDU to SFO?
The 5am–8am departure window is the strongest at 87.4% on time. The 5pm–8pm window is the weakest at 66.4%, 21 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 RDU to SFO?
June is the weakest month at 53.3% on time, compared with 90.9% in September. Across the year that is 38 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 RDU — the return legseparate record
- Raleigh-Durham International (RDU) delay statistics
- San Francisco International (SFO) delay statistics
- RDU to ATL, a related route86.5%
- LAX to SFO, a related route60.1%
- RDU to ORD, a related route74.3%
- United Airlines on-time record78.1%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. RDU to SFO and SFO to RDU 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.