Route reliability record
BOS→PHL
Boston to Philadelphia
- Flights
- 4,961
- Period
- July 2025 to June 2026
- Distance
- 280 mi
- Carriers
- 4
This route lands a B, about a point worse than the national rate of 77.6%. About one flight in four arrive 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 4,961 flights, of which Republic Airways flew 1,763 at 79.1% on time.
Republic Airways is the most reliable of the three carriers covered here at 79.1% on time across 1,763 flights.
Key figures
On time
76.5%
Arrivals under 15 minutes late, of 4,812 completed flights
Avg delay
87 min
Across delayed arrivals only, not all flights
Cancelled
2.92%
National rate is 1.81%
Best carrier
Republic
79.1% on time across 1,763 flights
These figures cover 4,961 flights between July 2025 and June 2026. Beyond the headline rate, 10.6% 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 BOS to PHL
The choice of carrier is not cosmetic here. Republic Airways arrives on time 79.1% of the time; JetBlue Airways manages 72.3%. Sample sizes sit next to every figure, because a two-point gap across 892 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 57 | 82.1% | 55 min | 1.75% | B |
| Republic Airways | 1,763 | 79.1% | 69 min | 3.29% | B− |
| American Airlines | 2,249 | 75.9% | 109 min | 2.85% | B |
| JetBlue Airways | 892 | 72.3% | 68 min | 2.47% | C |
Republic Airways cancels 3.3% 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 38 points, against 7 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am837 flights93.1%
- 8am–11am1,036 flights85.4%
- 11am–2pm879 flights79.2%
- 2pm–5pm981 flights69.9%
- 5pm–8pm856 flights62.8%
- 8pm–5am372 flights55.4%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 55.4% on time, against 93.1% 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 8am–11am window is the busiest, with 1,036 flights scheduled in it.
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.
November is the best month on the calendar at 84.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. October was the busiest month here, with 462 flights.
Across the week, Saturday is the strongest day at 84.7% on time and Sunday the weakest at 72.7%. 12 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 56% of the 99,000 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.
- 56%Late-arriving aircraft
- 27%Carrier
- 15%National Airspace System
- 2%Extreme weather
- 0%Security
56% 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 99,000 reported delay minutes here, that single category outweighs weather by 33 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 98,881 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 93.1% on time here.
Cancellations run at 2.92%, against 1.81% 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.6% 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 280 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 75.2% on time across 4,956 flights, within about a point 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 4,961 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 2.92% 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. 4,812 completed flights over 12 months sit behind that.
Common questions
BOS to PHL questions
How often is BOS 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 23.5% of the 4,961 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 BOS to PHL?
Republic Airways leads at 79.1% on time across 1,763 flights. JetBlue Airways is at the other end on 72.3%, a gap of 7 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 BOS to PHL?
The 5am–8am departure window is the strongest at 93.1% on time. The 8pm–5am window is the weakest at 55.4%, 38 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 October delays on BOS to PHL?
October is the weakest month at 67.5% on time, compared with 84.3% in November. 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
- PHL to BOS — the return legseparate record
- Boston Logan International (BOS) delay statistics
- Philadelphia International (PHL) delay statistics
- Frontier Airlines on-time record82.1%
- Republic Airways on-time record79.1%
- American Airlines on-time record75.9%
- Why the first flight of the morning is statistically safest
- What a cancellation rate actually tells you (and what it hides)
Direction matters. BOS to PHL and PHL to BOS 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.