Route reliability record

SAT→PHX

San Antonio to Phoenix

Flights: 2,512
Period: July 2025 to June 2026
Distance: 843 mi
Carriers: 4

This route lands a B+, 4 points better than the national rate of 77.6%. About one flight in six arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 2,512 flights, of which Southwest Airlines flew 1,390 at 83.3% on time.

Set against the rest of the country, this route's record is 4 points better than the US average of 77.6%. That gap is worth roughly 43 fewer late arrivals for every thousand flights.

On time

81.9%

Arrivals under 15 minutes late, of 2,496 completed flights

Avg delay

78 min

Across delayed arrivals only, not all flights

Cancelled

0.52%

National rate is 1.81%

Best carrier

Southwest

83.3% on time across 1,390 flights

These figures cover 2,512 flights between July 2025 and June 2026. The median arrival is 8 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Carrier by carrier

Which airline is most reliable on SAT to PHX

The two carriers here are closely matched: 3 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on SAT to PHX
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	1,390	83.3%	51 min	0.22%	B+
Frontier Airlinesthin sample	65	83.1%	57 min	0.00%	B+
American Airlines	1,018	80.6%	115 min	0.98%	B+
Envoy Airthin sample	39	64.1%	37 min	0.00%	D+

No carrier stands out. Southwest tops the table at 83.3%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 25 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am438 flights96.1%
8am–11am435 flights87.7%
11am–2pm406 flights87.8%
2pm–5pm515 flights74.7%
5pm–8pm524 flights72.0%
8pm–5am194 flights71.0%

Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 96.1% of the time, against 71.0% for the overnight window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 524 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 31 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, June worst

June is the worst month at 57.2% on time, 31 points below March, the best at 87.7%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. December was the busiest month here, with 252 flights.

Across the week, Tuesday is the strongest day at 89.0% on time and Sunday the weakest at 76.3%. 13 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 56% of the 35,000 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
56%
Carrier
27%
National Airspace System
9%
Extreme weather
7%
Security
0%

56% 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 35,000 reported delay minutes here, that single category outweighs weather by 8 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 35,195 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 96.1% on time here.

Cancellations are rare at 0.52%, below the national 1.81% 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

6.3% of arrivals land an hour or more late, close to the national 8.1%. 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 843 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 76.9% on time across 2,512 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 2,512 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 87.7% on time and June 57.2%, a swing of 31 points. If the dates move at all, move them out of June before you think about anything else. 2,496 completed flights over 12 months sit behind that.

Common questions

SAT to PHX questions

How often is SAT to PHX delayed?

About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.1% of the 2,512 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on SAT to PHX?

Southwest Airlines leads at 83.3% on time across 1,390 flights. American Airlines is at the other end on 80.6%, a gap of 3 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 SAT to PHX?

The 5am–8am departure window is the strongest at 96.1% on time. The 8pm–5am window is the weakest at 71.0%, 25 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 June delays on SAT to PHX?

June is the weakest month at 57.2% on time, compared with 87.7% in March. Across the year that is 31 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. SAT to PHX and PHX to SAT 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, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures