Carrier route record

F9SFO→PHX

Frontier Airlines · San Francisco to Phoenix

Flights: 278
Period: September 2025 to August 2026
Share of route: 6%
Carriers: 5

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

Frontier on SFO to PHX draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is close to two hours behind schedule. Build slack into anything you connect to. That rests on 278 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 572 at 85.2% on time.

SkyWest Airlines is the most reliable of the four carriers covered here at 85.2% on time across 572 flights.

On time

61.1%

Arrivals under 15 minutes late, of 270 completed flights

Avg delay

106 min

Across delayed arrivals only, not all flights

Cancelled

2.16%

National rate is 1.89%

Whole route

72.8%

Every carrier on SFO to PHX, 4,727 flights

These figures cover 278 flights between September 2025 and August 2026. Beyond the headline rate, 18.9% 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 SFO to PHX

Frontier flew 278 of the 4,727 flights on SFO to PHX, about 6% of it. Its 61.1% on time is 12 points worse than the route as a whole, which runs 72.8%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from SkyWest at 85.2% to Southwest at 58.8%.

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 85.2% of the time; Southwest Airlines manages 58.8%. 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 SFO to PHX
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	572	85.2%	75 min	0.70%	A+
United Airlines	1,488	79.9%	59 min	0.40%	B+
American Airlines	1,313	73.2%	98 min	0.91%	C+
Frontier Airlines (this page)thin sample	278	61.1%	106 min	2.16%	D
Southwest Airlines	1,076	58.8%	57 min	0.56%	D+

The spread between SkyWest and Southwest is 26 points, wide enough that it should decide the booking. On a hundred trips that is 26 more arrivals inside the on-time window.

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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–8am—
8am–11am21 flights—
11am–2pm7 flights—
2pm–5pm9 flights—
5pm–8pm123 flights60.7%
8pm–5am118 flights55.6%

Scale runs 45% to 65%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is the strongest at 60.7% on time. The full set of windows spans 5 points.

Across the year

Frontier on SFO to PHX through the year

Jul–Sep 202516 flights—
Oct–Dec 202559 flights44.8%
Jan–Mar 202670 flights75.4%
Apr–Jun 202677 flights65.8%
Jul–Sep 202656 flights56.9%

Scale runs 35% 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 61.1% on time across 278 flights.

Frontier on SFO to PHX did not run the same all year. Its best quarter was Jan–Mar 2026 at 75.4% on time and its weakest Oct–Dec 2025 at 44.8%, a swing of 31 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 90.3% on time and Sunday the weakest at 43.4%, a spread of 47 points.

Arrival by arrival

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

Frontier on SFO to PHX often beats the schedule: 72 of 270 completed flights, 27%, arrived 15 minutes or more early. The 105 late arrivals split 22 under half an hour, 32 between 30 and 60 minutes, and 51 an hour or more.

15+ min early72 flights26.7%
Within 15 min93 flights34.4%
15–29 min late22 flights8.1%
30–59 min late32 flights11.9%
1–2 hours late22 flights8.1%
2+ hours late29 flights10.7%

Scale runs 0% to 100%.

Share of 270 completed flights by arrival against schedule.

Time lost at the gate mostly stays lost. Of 109 departures that left 15 minutes late or more, only 12 made it up before arrival. 8 flights left on time and still arrived late.

The worst days

Worst days for Frontier on SFO to PHX

The latest arrival of the period was on 13 April 2026, 15 hours 7 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 SFO to PHX in the period
Date	Arrived late by	Largest filed cause
13 April 2026	15 hours 7 minutes	Late-arriving aircraft
17 May 2026	14 hours 22 minutes	Late-arriving aircraft
3 August 2026	13 hours 7 minutes	Carrier
15 July 2026	6 hours 37 minutes	Late-arriving aircraft
9 August 2026	5 hours 47 minutes	Carrier

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 74% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
74%
Carrier
17%
National Airspace System
8%
Extreme weather
0%

74% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 74 to one. The split is drawn from 11,134 reported delay minutes.

Cancellations sit at 2.16% against a national 1.89%, which is ordinary. Diversions add another 0.72%.

Connections and stage length

What a delay here costs

18.9% 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 65.8% on time across 278 flights, 5 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 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 SFO to PHX

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 61.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 270 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