Route reliability record
PHL→RDU
Philadelphia to Raleigh
- Flights
- 2,560
- Period
- July 2025 to June 2026
- Distance
- 337 mi
- Carriers
- 4
This route sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 2,560 flights, of which Frontier Airlines flew 585 at 81.2% on time.
Frontier Airlines is the most reliable of the three carriers covered here at 81.2% on time across 585 flights.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 2,486 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
2.77%
National rate is 1.81%
Best carrier
Frontier
81.2% on time across 585 flights
These figures cover 2,560 flights between July 2025 and June 2026. Beyond the headline rate, 10.7% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on PHL to RDU
The choice of carrier is not cosmetic here. Frontier Airlines arrives on time 81.2% of the time; American Airlines manages 71.3%. Sample sizes sit next to every figure, because a two-point gap across 1,105 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 215 | 83.2% | 75 min | 3.26% | B− |
| Frontier Airlines | 585 | 81.2% | 68 min | 2.56% | B |
| PSA Airlines | 655 | 72.9% | 80 min | 3.51% | C− |
| American Airlines | 1,105 | 71.3% | 81 min | 2.35% | C |
PSA Airlines cancels 3.5% 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.
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 16 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am255 flights83.7%
- 8am–11am492 flights81.6%
- 11am–2pm441 flights78.8%
- 2pm–5pm588 flights69.8%
- 5pm–8pm475 flights67.8%
- 8pm–5am309 flights72.2%
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 83.7% of the time, against 67.8% for the evening window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 588 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 25 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.
December is the weak month at 60.6% on time, against 85.7% in May. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. June was the busiest month here, with 250 flights.
Across the week, Tuesday is the strongest day at 80.2% on time and Sunday the weakest at 70.6%. 10 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. Late-arriving aircraft accounts for 57% of the 48,000 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.
- 57%Late-arriving aircraft
- 27%Carrier
- 11%National Airspace System
- 4%Extreme weather
- 0%Security
57% 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 48,000 reported delay minutes here, that single category outweighs weather by 16 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 48,449 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 83.7% on time here.
Cancellations run at 2.77%, against 1.81% nationally. That is roughly one flight in 40 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.7% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 337 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg runs 73.5% on time across 2,562 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,560 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.
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 85.7% on time and December 60.6%, a swing of 25 points. If the dates move at all, move them out of December before you think about anything else. 2,486 completed flights over 12 months sit behind that.
Common questions
PHL to RDU questions
How often is PHL to RDU delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.0% of the 2,560 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on PHL to RDU?
Frontier Airlines leads at 81.2% on time across 585 flights. American Airlines is at the other end on 71.3%, a gap of 10 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 RDU?
The 5am–8am departure window is the strongest at 83.7% on time. The 5pm–8pm window is the weakest at 67.8%, 16 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 December delays on PHL to RDU?
December is the weakest month at 60.6% on time, compared with 85.7% in May. Across the year that is 25 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
- RDU to PHL — the return legseparate record
- Philadelphia International (PHL) delay statistics
- Raleigh-Durham International (RDU) delay statistics
- Republic Airways on-time record83.2%
- Frontier Airlines on-time record81.2%
- PSA Airlines on-time record72.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. PHL to RDU and RDU to PHL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.