Route reliability record
MIA→PHL
Miami to Philadelphia
- Flights
- 3,158
- Period
- July 2025 to June 2026
- Distance
- 1,013 mi
- Carriers
- 3
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, 2 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 3,158 flights, with a median arrival 6 minutes early.
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
75.8%
Arrivals under 15 minutes late, of 3,082 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
2.28%
National rate is 1.81%
Best carrier
American
76.4% on time across 2,569 flights
These figures cover 3,158 flights between July 2025 and June 2026. Beyond the headline rate, 9.7% 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 MIA to PHL
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 |
|---|---|---|---|---|---|
| American Airlines | 2,569 | 76.4% | 79 min | 2.10% | B |
| Spirit Airlinesthin sample | 236 | 73.9% | 66 min | 4.24% | C− |
| Frontier Airlinesthin sample | 353 | 72.5% | 91 min | 2.27% | C |
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 23 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–8am467 flights91.8%
- 8am–11am430 flights85.9%
- 11am–2pm139 flights79.1%
- 2pm–5pm715 flights69.2%
- 5pm–8pm696 flights70.7%
- 8pm–5am711 flights69.8%
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 91.8% of the time, against 69.2% for the afternoon window. That is 23 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 715 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.
July is the worst month at 65.1% on time, 17 points below October, the best at 81.9%. 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. April was the busiest month here, with 298 flights.
Across the week, Thursday is the strongest day at 80.0% on time and Sunday the weakest at 64.7%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 59,000 reported delay minutes.
- 41%Carrier
- 39%Late-arriving aircraft
- 17%National Airspace System
- 3%Extreme weather
- 0%Security
39% 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 59,000 reported delay minutes here, that single category outweighs weather by 11 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 59,306 reported delay minutes.
The largest share of delay minutes, 41%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 24,000 of the 59,000 delay minutes reported here.
Cancellations sit at 2.28% against a national 1.81%, which is ordinary. Diversions add another 0.13%.
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. 9.7% 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.
The 1,013 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 77.2% on time across 3,158 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 3,158 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. October runs 81.9% on time and July 65.1%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 3,082 completed flights over 12 months sit behind that.
Common questions
MIA to PHL questions
How often is MIA 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 24.2% of the 3,158 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is MIA to PHL compared with the rest of the country?
75.8% of flights arrive on time here against a national 77.6%, a difference of 2 points against it. That is worth a B on this site's grading scale.
What time of day has the fewest delays on MIA to PHL?
The 5am–8am departure window is the strongest at 91.8% on time. The 2pm–5pm window is the weakest at 69.2%, 23 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 MIA to PHL?
July is the weakest month at 65.1% on time, compared with 81.9% in October. 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 MIA — the return legseparate record
- Miami International (MIA) delay statistics
- Philadelphia International (PHL) delay statistics
- American Airlines on-time record76.4%
- Spirit Airlines on-time record73.9%
- Frontier 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. MIA to PHL and PHL to MIA 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.