Route reliability record
RDU→SFO
Raleigh to San Francisco
- Flights
- 895
- Period
- July 2025 to June 2026
- Distance
- 2,400 mi
- Carriers
- 1
This route lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 895 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 87.9% of the time and Tuesday flights 91.3%, against 80.5% for the route overall.
The US average over the same twelve months is 77.6%, 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
80.5%
Arrivals under 15 minutes late, of 889 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
0.22%
National rate is 1.81%
Best carrier
United
80.5% on time across 895 flights
These figures cover 895 flights between July 2025 and June 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.
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 | 895 | 80.5% | 69 min | 0.22% | 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.
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 19 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–8am283 flights87.9%
- 8am–11am264 flights85.1%
- 11am–2pm—
- 2pm–5pm50 flights84.0%
- 5pm–8pm298 flights69.0%
- 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 87.9% of the time, against 69.0% for the evening window. That is 19 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 298 flights scheduled in it.
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 91.3% on time and Thursday the weakest at 74.8%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. National Airspace System accounts for 49% of the 12,000 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.
- 49%National Airspace System
- 29%Late-arriving aircraft
- 20%Carrier
- 2%Extreme weather
49% 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 5,849 minutes out of 12,000, against a national NAS share of 21%. The split is drawn from 11,966 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 87.9% on time here.
Cancellations are rare at 0.22%, 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 actually costs
6.7% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over 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 89.6% on time across 896 flights, 9 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 9 points of difference.
One caution: this is a thin sample. 895 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. 895 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 80.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 889 completed flights over 12 months sit behind that.
Common questions
RDU to SFO questions
How often is RDU to SFO delayed?
About 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 19.5% of the 895 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is RDU to SFO compared with the rest of the country?
80.5% of flights arrive on time here against a national 77.6%, a difference of 3 points 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 87.9% on time. The 5pm–8pm window is the weakest at 69.0%, 19 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 route87.6%
- LAX to SFO, a related route64.8%
- RDU to ORD, a related route74.4%
- United Airlines on-time record80.5%
- The best time of day to fly, according to 7.04 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.