Route reliability record
RDU→PHL
Raleigh to Philadelphia
- Flights
- 2,562
- Period
- July 2025 to June 2026
- Distance
- 337 mi
- Carriers
- 4
This route carries a cancellation problem, not just a delay problem: 3.5% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 2,562 flights, of which Frontier Airlines flew 585 at 74.0% on time.
Frontier Airlines is the most reliable of the three carriers covered here at 74.0% on time across 585 flights.
Key figures
On time
73.5%
Arrivals under 15 minutes late, of 2,469 completed flights
Avg delay
94 min
Across delayed arrivals only, not all flights
Cancelled
3.51%
National rate is 1.81%
Best carrier
Frontier
74.0% on time across 585 flights
These figures cover 2,562 flights between July 2025 and June 2026. Beyond the headline rate, 11.3% 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 RDU to PHL
The three 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 | 216 | 85.0% | 66 min | 3.70% | A− |
| Frontier Airlines | 585 | 74.0% | 99 min | 4.62% | C− |
| American Airlines | 1,105 | 72.5% | 101 min | 2.35% | C |
| PSA Airlines | 656 | 70.8% | 83 min | 4.42% | C− |
Frontier Airlines cancels 4.6% 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 28 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am366 flights90.7%
- 8am–11am509 flights81.6%
- 11am–2pm540 flights73.3%
- 2pm–5pm456 flights63.3%
- 5pm–8pm483 flights63.2%
- 8pm–5am208 flights68.9%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 63.2% on time, against 90.7% 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 11am–2pm window is the busiest, with 540 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 26 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.
July is the worst month at 57.5% on time, 26 points below April, the best at 83.3%. 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. June was the busiest month here, with 249 flights.
Across the week, Tuesday is the strongest day at 80.2% on time and Thursday the weakest at 67.4%. 13 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 59% of the 61,000 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.
- 59%Late-arriving aircraft
- 23%Carrier
- 14%National Airspace System
- 4%Extreme weather
- 0%Security
59% 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 61,000 reported delay minutes here, that single category outweighs weather by 13 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 61,335 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 90.7% on time here.
Cancellations run at 3.51%, against 1.81% nationally. That is about 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.3% 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 75.0% on time across 2,560 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 2,562 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 delay figures matter less here than the 3.51% 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. 2,469 completed flights over 12 months sit behind that.
Common questions
RDU to PHL questions
How often is RDU to PHL 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 26.5% of the 2,562 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on RDU to PHL?
Frontier Airlines leads at 74.0% on time across 585 flights. PSA Airlines is at the other end on 70.8%, 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 PHL?
The 5am–8am departure window is the strongest at 90.7% on time. The 5pm–8pm window is the weakest at 63.2%, 28 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 July delays on RDU to PHL?
July is the weakest month at 57.5% on time, compared with 83.3% in April. Across the year that is 26 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
- PHL to RDU — the return legseparate record
- Raleigh-Durham International (RDU) delay statistics
- Philadelphia International (PHL) delay statistics
- Republic Airways on-time record85.0%
- Frontier Airlines on-time record74.0%
- American Airlines on-time record72.5%
- 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. RDU to PHL and PHL to RDU 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.