Route reliability record
RDU→BOS
Raleigh to Boston
- Flights
- 2,847
- Period
- September 2025 to August 2026
- Distance
- 612 mi
- Carriers
- 4
This route lands a B, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 2,847 RDU to BOS flights, of which Delta Air Lines flew 1,435 at 79.6% on time.
Best time to fly RDU to BOS: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 92.0% of the time and Tuesday flights 82.0%, against 78.5% 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
78.5%
Arrivals under 15 minutes late, of 2,763 completed flights
Avg delay
83 min
Across delayed arrivals only, not all flights
Cancelled
2.95%
National rate is 1.89%
Best carrier
Delta
79.6% on time across 1,435 flights
These figures cover 2,847 flights between September 2025 and August 2026. Beyond the headline rate, 9.7% 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 RDU to BOS
The two carriers here are closely matched: 3 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 |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 134 | 81.1% | 87 min | 5.22% | B− |
| Delta Air Lines | 1,435 | 79.6% | 89 min | 2.72% | B |
| Frontier Airlinesthin sample | 174 | 79.3% | 90 min | 0.00% | B+ |
| JetBlue Airways | 1,104 | 76.7% | 75 min | 3.44% | B− |
JetBlue Airways cancels 3.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
Flights on RDU to BOS
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 Raleigh to Boston
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. RDU → BOSRaleigh to Boston | Delta Air Lines | 77.4% | 79.6% | 2.72% | 5am–8am, Sat | DL 1054 07:00 |
| 2. RDU → BOSRaleigh to Boston | JetBlue Airways | 74.1% | 76.7% | 3.44% | 5am–8am, Sat | B6 484 09:23 |
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 31 points, against 3 points between the best and worst carrier.
- 5am–8am646 flights92.0%
- 8am–11am789 flights85.6%
- 11am–2pm355 flights75.9%
- 2pm–5pm518 flights60.6%
- 5pm–8pm313 flights73.8%
- 8pm–5am226 flights67.3%
Scale runs 50% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.0% of the time, against 60.6% for the afternoon window. That is 31 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 789 flights scheduled in it.
Explore
Filter RDU to BOS 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 BOS, the best departure window is 5am–8am at 92.0% on time and the worst is 2pm–5pm at 60.6%, a wide gap of 31.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.0%
- 8–11am85.6%
- 11am–2pm75.9%
- 2–5pm60.6%
- 5–8pm73.8%
- 8pm–5am67.3%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 17 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.
Delays peak in September, when the on-time rate falls to 66.4%. February is the strongest month at 83.8%. Moving a flexible trip across that boundary buys 17 points. October was the busiest month here, with 291 flights.
Across the week, Tuesday is the strongest day at 82.0% on time and Monday the weakest at 75.5%, a spread of 7 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 45% of the 49,000 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Late-arriving aircraft
- 36%National Airspace System
- 19%Carrier
- 1%Extreme weather
45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 49,000 reported delay minutes here, that single category outweighs weather by 45 to one. The split is drawn from 49,354 reported delay minutes.
36% 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 18,000 minutes out of 49,000, against a national NAS share of 21%.
Cancellations run at 2.95%, against 1.89% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
9.7% 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.
The 612 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 75.5% on time across 2,848 flights, 3 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 3 points of difference.
The sample behind these figures is 2,847 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 BOS after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 2.95% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,763 completed flights over 12 months sit behind that.
Common questions
RDU to BOS questions
How often is RDU to BOS 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 21.5% of the 2,847 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on RDU to BOS?
Delta Air Lines leads at 79.6% on time across 1,435 flights. JetBlue Airways is at the other end on 76.7%, a gap of 3 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 RDU to BOS?
The 5am–8am departure window is the strongest at 92.0% on time. The 2pm–5pm window is the weakest at 60.6%, 31 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 September delays on RDU to BOS?
September is the weakest month at 66.4% on time, compared with 83.8% in February. Across the year that is 17 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
- BOS to RDU — the return legseparate record
- Raleigh-Durham International (RDU) delay statistics
- Boston Logan International (BOS) delay statistics
- Republic Airways on RDU to BOS81.1%
- Delta Air Lines on RDU to BOS79.6%
- Frontier Airlines on RDU to BOS79.3%
- JetBlue Airways on RDU to BOS76.7%
- RDU to ATL, a related route86.5%
- DCA to BOS, a related route70.1%
- RDU to ORD, a related route74.3%
- Republic Airways on-time record81.1%
- Delta Air Lines on-time record79.6%
- Frontier Airlines on-time record79.3%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. RDU to BOS and BOS 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.