Carrier route record

WNLAX→SJC

Southwest Airlines · Los Angeles to San Jose

Flights: 1,822
Period: July 2025 to June 2026
Share of route: 41%
Carriers: 6

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

Southwest on LAX to SJC lands a B+, 4 points better than the national rate of 77.6%. Roughly 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 1,822 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 2,049 at 91.4% on time.

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

On time

81.5%

Arrivals under 15 minutes late, of 1,809 completed flights

Avg delay

48 min

Across delayed arrivals only, not all flights

Cancelled

0.66%

National rate is 1.81%

Whole route

86.6%

Every carrier on LAX to SJC, 4,429 flights

These figures cover 1,822 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

Southwest against every carrier on LAX to SJC

Southwest flew 1,822 of the 4,429 flights on LAX to SJC, about 41% of it. Its 81.5% on time is 5 points worse than the route as a whole, which runs 86.6%. Ranked by on-time rate it is number four of six carriers on the route, where the range runs from United at 100.0% to American at 66.7%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The two carriers here are closely matched: 5 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 LAX to SJC
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlinesthin sample	1	100.0%	—	0.00%	A+
SkyWest Airlines	2,049	91.4%	55 min	0.34%	A+
Delta Air Lines	455	86.4%	61 min	2.86%	A
Southwest Airlines (this page)	1,822	81.5%	48 min	0.66%	B+
Frontier Airlinesthin sample	96	80.6%	53 min	3.12%	B−
American Airlinesthin sample	6	66.7%	39 min	0.00%	C+

No carrier stands out. SkyWest tops the table at 91.4%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 38 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am338 flights95.8%
8am–11am327 flights92.3%
11am–2pm225 flights85.8%
2pm–5pm337 flights84.8%
5pm–8pm387 flights67.9%
8pm–5am208 flights57.5%

Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 57.5% on time, against 95.8% for the 5am–8am 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 5pm–8pm window is the busiest, with 387 flights scheduled in it.

Across the year

Southwest on LAX to SJC through the year

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

June is the worst month at 66.7% on time, 23 points below January, the best at 89.7%. 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. October was the busiest month here, with 179 flights.

Across the week, Tuesday is the strongest day at 86.5% on time and Sunday the weakest at 73.6%. 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 71% of the 16,000 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
71%
Carrier
26%
National Airspace System
3%
Security
0%

71% 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 16,000 reported delay minutes here, that single category outweighs weather by 71 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 16,141 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 95.8% on time here.

Cancellations are rare at 0.66%, 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 4.6% 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.

At 308 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.

The return leg runs 78.9% on time across 1,823 flights, within 3 points 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 1,822 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 LAX to SJC

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 89.7% on time and June 66.7%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 1,809 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