Carrier route record

F9SFO→PHX

Frontier Airlines · San Francisco to Phoenix

Flights: 263
Period: July 2025 to June 2026
Share of route: 6%
Carriers: 5

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

Frontier on SFO to PHX draws a D−. Roughly one flight in two 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 263 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 538 at 87.3% on time.

SkyWest Airlines is the most reliable of the four carriers covered here at 87.3% on time across 538 flights.

On time

59.6%

Arrivals under 15 minutes late, of 255 completed flights

Avg delay

98 min

Across delayed arrivals only, not all flights

Cancelled

3.04%

National rate is 1.81%

Whole route

74.4%

Every carrier on SFO to PHX, 4,643 flights

These figures cover 263 flights between July 2025 and June 2026. Beyond the headline rate, 20.8% 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 SFO to PHX

Frontier flew 263 of the 4,643 flights on SFO to PHX, about 6% of it. Its 59.6% on time is 15 points worse than the route as a whole, which runs 74.4%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from SkyWest at 87.3% to Frontier at 59.6%.

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 87.3% of the time; Southwest Airlines manages 61.1%. Sample sizes sit next to every figure, because a two-point gap across 1,079 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	538	87.3%	67 min	0.74%	A+
United Airlines	1,443	81.0%	59 min	0.49%	B+
American Airlines	1,320	75.7%	106 min	0.83%	B+
Southwest Airlines	1,079	61.1%	57 min	0.56%	D+
Frontier Airlines (this page)thin sample	263	59.6%	98 min	3.04%	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.

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 11 points, against 26 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am21 flights—
11am–2pm7 flights—
2pm–5pm9 flights—
5pm–8pm67 flights63.6%
8pm–5am159 flights52.9%

Scale runs 45% to 70%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 52.9% on time, against 63.6% for the 5pm–8pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 159 flights scheduled in it.

Across the year

Frontier on SFO to PHX through the year

Jul–Sep 202557 flights46.2%
Oct–Dec 202559 flights44.8%
Jan–Mar 202670 flights75.4%
Apr–Jun 202677 flights65.8%

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 59.6% on time across 263 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 66 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, Monday is the strongest day at 60.8% on time and Sunday the weakest at 43.4%. 17 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 85% of the 10,000 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
85%
Carrier
9%
National Airspace System
6%
Extreme weather
0%

85% 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 10,000 reported delay minutes here, that single category outweighs weather by 85 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 10,081 reported delay minutes.

Cancellations run at 3.04%, against 1.81% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

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. 20.8% 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 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. 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 68.6% on time across 263 flights, 9 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 9 points of difference.

One caution: this is a thin sample. 263 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: the delay figures matter less here than the 3.04% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5pm–8pm departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 255 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