Carrier route record

F9PHX→SFO

Frontier Airlines · Phoenix to San Francisco

Flights: 278
Period: September 2025 to August 2026
Share of route: 6%
Carriers: 6

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Frontier Airlines.

Frontier on PHX to SFO draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 278 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,489 at 67.7% on time.

United Airlines is the most reliable of the four carriers covered here at 67.7% on time across 1,489 flights.

On time

65.8%

Arrivals under 15 minutes late, of 275 completed flights

Avg delay

64 min

Across delayed arrivals only, not all flights

Cancelled

1.08%

National rate is 1.89%

Whole route

63.6%

Every carrier on PHX to SFO, 4,728 flights

These figures cover 278 flights between September 2025 and August 2026. Beyond the headline rate, 12.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.

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Carrier by carrier

Frontier against every carrier on PHX to SFO

Frontier flew 278 of the 4,728 flights on PHX to SFO, about 6% of it. Its 65.8% on time is 2 points better than the route as a whole, which runs 63.6%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from Envoy at 100.0% to Southwest at 57.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. United Airlines arrives on time 67.7% of the time; Southwest Airlines manages 57.7%. Sample sizes sit next to every figure, because a two-point gap across 1,076 flights means less than a ten-point one.

On-time performance by carrier on PHX to SFO
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Airthin sample	1	100.0%	—	0.00%	A+
United Airlines	1,489	67.7%	59 min	0.47%	C+
Frontier Airlines (this page)thin sample	278	65.8%	64 min	1.08%	C
SkyWest Airlines	572	63.7%	67 min	0.17%	D+
American Airlines	1,312	63.2%	77 min	0.91%	D+
Southwest Airlines	1,076	57.7%	56 min	0.37%	D+

United leads Southwest by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

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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 278 flights.

5am–8am27 flights—
8am–11am21 flights—
11am–2pm6 flights—
2pm–5pm191 flights64.2%
5pm–8pm33 flights65.6%
8pm–5am—

Scale runs 55% to 70%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is the strongest at 65.6% on time. The full set of windows spans about a point.

Across the year

Frontier on PHX to SFO through the year

Jul–Sep 202516 flights—
Oct–Dec 202559 flights77.6%
Jan–Mar 202670 flights85.5%
Apr–Jun 202677 flights54.5%
Jul–Sep 202656 flights47.3%

Scale runs 40% to 90%. 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 65.8% on time across 278 flights.

Frontier on PHX to SFO did not run the same all year. Its best quarter was Jan–Mar 2026 at 85.5% on time and its weakest Jul–Sep 2026 at 47.3%, a swing of 38 points on roughly 70 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Saturday is the strongest day at 71.0% on time and Sunday the weakest at 62.3%, a spread of 9 points.

Arrival by arrival

How late Frontier on PHX to SFO runs when it is late

Frontier on PHX to SFO often beats the schedule: 88 of 275 completed flights, 32%, arrived 15 minutes or more early. The 94 late arrivals split 32 under half an hour, 29 between 30 and 60 minutes, and 33 an hour or more.

15+ min early88 flights32.0%
Within 15 min93 flights33.8%
15–29 min late32 flights11.6%
30–59 min late29 flights10.5%
1–2 hours late21 flights7.6%
2+ hours late12 flights4.4%

Scale runs 0% to 100%.

Share of 275 completed flights by arrival against schedule.

20 of 109 late departures made up the time and arrived on time, 18% of them. Only 5 left on time and still arrived late.

The worst days

Worst days for Frontier on PHX to SFO

The latest arrival of the period was on 29 July 2026, 5 hours 4 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.

The latest arrivals of Frontier on PHX to SFO in the period
Date	Arrived late by	Largest filed cause
29 July 2026	5 hours 4 minutes	Late-arriving aircraft
21 June 2026	3 hours 43 minutes	Late-arriving aircraft
21 December 2025	3 hours 36 minutes	National Airspace System
5 November 2025	3 hours 34 minutes	National Airspace System
15 February 2026	3 hours 32 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

National Airspace System accounts for 45% of the 5,991 delay minutes carriers reported here, and the remaining four split what is left.

National Airspace System
45%
Late-arriving aircraft
42%
Carrier
13%

42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,991 reported delay minutes here, that single category outweighs weather by 42 to one. The split is drawn from 5,991 reported delay minutes.

45% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,724 minutes out of 5,991, against a national NAS share of 21%.

Cancellations sit at 1.08% against a national 1.89%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

12.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.

The 651 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.

The return leg is a different operation and performs like one: it runs 61.1% on time across 278 flights, 5 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 5 points of difference.

One caution: this is a thin sample. 278 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 PHX to SFO

Put together: treat all of this as provisional. 278 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 65.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 275 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures