Carrier route record

WNSJC→PHX

Southwest Airlines · San Jose to Phoenix

Flights: 1,879
Period: July 2025 to June 2026
Share of route: 62%
Carriers: 4

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

Southwest on SJC to PHX lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 1,879 flights, with a median arrival 4 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate Southwest on SJC to PHX from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

78.6%

Arrivals under 15 minutes late, of 1,866 completed flights

Avg delay

48 min

Across delayed arrivals only, not all flights

Cancelled

0.64%

National rate is 1.81%

Whole route

82.0%

Every carrier on SJC to PHX, 3,031 flights

These figures cover 1,879 flights between July 2025 and June 2026. The median arrival is 4 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

Southwest against every carrier on SJC to PHX

Southwest flew 1,879 of the 3,031 flights on SJC to PHX, most of the route. Its 78.6% on time is 3 points worse than the route as a whole, which runs 82.0%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from Envoy at 89.9% to Southwest at 78.6%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on SJC to PHX
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Airthin sample	220	89.9%	50 min	0.91%	A+
American Airlines	639	87.5%	102 min	0.78%	A+
SkyWest Airlinesthin sample	293	85.5%	97 min	1.02%	A
Southwest Airlines (this page)	1,879	78.6%	48 min	0.64%	B+

Departure window

When Southwest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 30 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am322 flights95.9%
8am–11am362 flights93.1%
11am–2pm270 flights77.6%
2pm–5pm408 flights65.8%
5pm–8pm316 flights69.6%
8pm–5am201 flights65.8%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 95.9% of the time, against 65.8% for the overnight window. That is 30 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 408 flights scheduled in it.

Across the year

Southwest on SJC to PHX through the year

Darker means more delays. Figures are on-time percentages.January best, June worst

June is the worst month at 63.6% on time, 25 points below January, the best at 88.4%. 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. May was the busiest month here, with 180 flights.

Across the week, Saturday is the strongest day at 85.8% on time and Sunday the weakest at 73.2%. 13 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 61% of the 19,000 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
61%
Carrier
23%
National Airspace System
15%
Extreme weather
1%

61% 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 19,000 reported delay minutes here, that single category outweighs weather by 54 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 18,949 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 95.9% on time here.

Cancellations are rare at 0.64%, 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 costs

Badly late arrivals are rare here: only 4.9% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 621 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 runs 77.7% on time across 1,866 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,879 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 Southwest on SJC to PHX

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 88.4% on time and June 63.6%, a swing of 25 points. If the dates move at all, move them out of June before you think about anything else. 1,866 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