Route reliability record

SFO→PHX

San Francisco to Phoenix

Flights: 4,622
Period: June 2025 to May 2026
Distance: 651 mi
Carriers: 5

This route sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.4%. The late ones land a little over an hour behind schedule. That rests on 4,622 flights, of which SkyWest Airlines flew 516 at 87.3% on time.

SkyWest Airlines is the most reliable of the four carriers covered here at 87.3% on time across 516 flights.

On time

75.6%

Arrivals under 15 minutes late, of 4,576 completed flights

Avg delay

75 min

Across delayed arrivals only, not all flights

Cancelled

0.80%

National rate is 1.80%

Best carrier

SkyWest

87.3% on time across 516 flights

These figures cover 4,622 flights between June 2025 and May 2026. Beyond the headline rate, 8.5% 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

Which airline is most reliable on SFO to PHX

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 87.3% of the time; Southwest Airlines manages 63.2%. 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	516	87.3%	65 min	0.78%	A+
United Airlines	1,452	81.6%	59 min	0.48%	B+
American Airlines	1,321	78.1%	112 min	0.83%	B+
Southwest Airlines	1,079	63.2%	56 min	0.56%	D+
Frontier Airlinesthin sample	254	56.7%	96 min	3.54%	D−

The spread between SkyWest and Southwest is 24 points, wide enough that it should decide the booking. On a hundred trips that is 24 more arrivals inside the on-time window.

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 28 points, against 24 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am838 flights93.5%
8am–11am816 flights78.3%
11am–2pm929 flights70.2%
2pm–5pm960 flights69.0%
5pm–8pm658 flights72.7%
8pm–5am421 flights66.0%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 93.5% of the time, against 66.0% for the overnight window. That is 28 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.

Across the year

When delays peak on this route

This route's year swings by 16 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

Darker means more delays. Figures are on-time percentages.March best, November worst

Delays peak in November, when the on-time rate falls to 68.3%. March is the strongest month at 84.1%. Moving a flexible trip across that boundary buys 16 points.

Across the week, Saturday is the strongest day at 81.9% on time and Monday the weakest at 70.3%. 12 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 55% of the 84,000 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
55%
Carrier
34%
National Airspace System
10%
Extreme weather
1%
Security
0%

55% 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 84,000 reported delay minutes here, that single category outweighs weather by 55 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 largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 29,000 of the 84,000 delay minutes reported here.

Cancellations are rare at 0.80%, below the national 1.80% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here actually costs

8.5% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the a little over an hour kind, which a normal layover absorbs.

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 70.7% on time across 4,625 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.

The sample behind these figures is 4,622 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 84.1% on time and November 68.3%, a swing of 16 points. If the dates move at all, move them out of November before you think about anything else.

Common questions

SFO to PHX questions

How often is SFO to PHX delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.4% of the 4,622 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on SFO to PHX?

SkyWest Airlines leads at 87.3% on time across 516 flights. Southwest Airlines is at the other end on 63.2%, a gap of 24 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on SFO to PHX?

The 5am–8am departure window is the strongest at 93.5% on time. The 8pm–5am window is the weakest at 66.0%, 28 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are November delays on SFO to PHX?

November is the weakest month at 68.3% on time, compared with 84.1% in March. Across the year that is 16 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. SFO to PHX and PHX to SFO are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.

Key figures