Carrier route record

F9PHL→MIA

Frontier Airlines · Philadelphia to Miami

Flights: 354
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 PHL to MIA draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 354 flights, with a median arrival 3 minutes early.

The national on-time rate over the same period is 77.6%, so Frontier on PHL to MIA runs 11 points behind the country as a whole. Across a thousand flights that is about 110 extra late arrivals.

On time

66.6%

Arrivals under 15 minutes late, of 347 completed flights

Avg delay

83 min

Across delayed arrivals only, not all flights

Cancelled

1.98%

National rate is 1.81%

Whole route

77.2%

Every carrier on PHL to MIA, 3,158 flights

These figures cover 354 flights between July 2025 and June 2026. Beyond the headline rate, 15.6% 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

Frontier against every carrier on PHL to MIA

Frontier flew 354 of the 3,158 flights on PHL to MIA, about 11% of it. Its 66.6% on time is 11 points worse than the route as a whole, which runs 77.2%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from American at 78.8% to Frontier at 66.6%. 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.

On-time performance by carrier on PHL to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlines	2,569	78.8%	87 min	1.99%	B
Spirit Airlinesthin sample	235	76.2%	55 min	2.98%	B
Frontier Airlines (this page)thin sample	354	66.6%	83 min	1.98%	C

Departure window

When Frontier runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 354 flights.

5am–8am30 flights—
8am–11am27 flights—
11am–2pm44 flights61.4%
2pm–5pm30 flights70.0%
5pm–8pm199 flights62.9%
8pm–5am24 flights—

Scale runs 55% to 75%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 61.4% on time against 70.0% for 2pm–5pm. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5pm–8pm window is the busiest, with 199 flights scheduled in it.

Across the year

Frontier on PHL to MIA through the year

Jul–Sep 202563 flights65.1%
Oct–Dec 202570 flights67.2%
Jan–Mar 2026105 flights67.3%
Apr–Jun 2026116 flights66.4%

Scale runs 55% to 75%. 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 66.6% on time across 354 flights.

Quarter by quarter Frontier on PHL to MIA held fairly steady: 65.1% in Jul–Sep 2025, 67.2% in Oct–Dec 2025, 67.3% in Jan–Mar 2026 and 66.4% in Apr–Jun 2026. A spread of 2 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 71.9% on time and Saturday the weakest at 59.6%. 12 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 51% of the 9,666 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.

Late-arriving aircraft
51%
Carrier
27%
National Airspace System
21%
Extreme weather
2%

51% 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 9,666 reported delay minutes here, that single category outweighs weather by 30 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 9,666 reported delay minutes.

Cancellations sit at 1.98% 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. 15.6% 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.

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 72.5% on time across 353 flights, 6 points above 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. 354 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 PHL to MIA

Put together: treat all of this as provisional. 354 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 66.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 347 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures