Carrier route record
F9MIA→PHL
Frontier Airlines · Miami to Philadelphia
- Flights
- 353
- Period
- July 2025 to June 2026
- Share of route
- 11%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on MIA to PHL sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 353 flights, with a median arrival 4 minutes early.
The national on-time rate over the same period is 77.6%, so Frontier on MIA to PHL runs 5 points behind the country as a whole. Across a thousand flights that is about 51 extra late arrivals.
Key figures
On time
72.5%
Arrivals under 15 minutes late, of 345 completed flights
Avg delay
91 min
Across delayed arrivals only, not all flights
Cancelled
2.27%
National rate is 1.81%
Whole route
75.8%
Every carrier on MIA to PHL, 3,158 flights
These figures cover 353 flights between July 2025 and June 2026. Beyond the headline rate, 14.2% 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
Frontier against every carrier on MIA to PHL
Frontier flew 353 of the 3,158 flights on MIA to PHL, about 11% of it. Its 72.5% on time is 3 points worse than the route as a whole, which runs 75.8%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from American at 76.4% to Frontier at 72.5%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 Airlines (this page)thin sample | 353 | 72.5% | 91 min | 2.27% | C |
Departure window
When Frontier runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 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–8am21 flights—
- 8am–11am39 flights79.5%
- 11am–2pm36 flights88.6%
- 2pm–5pm72 flights63.8%
- 5pm–8pm12 flights—
- 8pm–5am173 flights69.4%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 88.6% on time, ahead of 2pm–5pm at 63.8%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 8pm–5am window is the busiest, with 173 flights scheduled in it.
Across the year
Frontier on MIA to PHL through the year
- Jul–Sep 202563 flights76.2%
- Oct–Dec 202570 flights71.2%
- Jan–Mar 2026103 flights67.7%
- Apr–Jun 2026117 flights75.2%
Scale runs 60% to 80%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 72.5% on time across 353 flights.
Quarter by quarter Frontier on MIA to PHL held fairly steady: 76.2% in Jul–Sep 2025, 71.2% in Oct–Dec 2025, 67.7% in Jan–Mar 2026 and 75.2% in Apr–Jun 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
Across the week, Friday is the strongest day at 78.1% on time and Sunday the weakest at 58.5%. 20 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 66% of the 8,662 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.
- 66%Late-arriving aircraft
- 23%Carrier
- 10%National Airspace System
- 1%Extreme weather
66% 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 8,662 reported delay minutes here, that single category outweighs weather by 66 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 8,662 reported delay minutes.
Cancellations sit at 2.27% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.2% 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 is a different operation and performs like one: it runs 66.6% on time across 354 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 353 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Frontier on MIA to PHL
Put together: treat all of this as provisional. 353 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 72.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 345 completed flights over 12 months sit behind that.
Related
Where to go next
- MIA to PHL, every carrier
- Frontier on PHL to MIA, the return leg
- American Airlines on MIA to PHL76.4%
- Spirit Airlines on MIA to PHL73.9%
- Frontier Airlines network-wide record
- Miami International (MIA) delay statistics
- Philadelphia International (PHL) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.