Route reliability record

SJC→LAX

San Jose to Los Angeles

Flights: 4,405
Period: June 2025 to May 2026
Distance: 308 mi
Carriers: 6

This route earns a A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.4%. When something does go wrong the average delay runs roughly 55 minutes. That rests on 4,405 flights, of which SkyWest Airlines flew 2,153 at 92.5% on time.

Set against the rest of the country, this route's record is 10 points better than the US average of 77.4%. That gap is worth roughly 99 fewer late arrivals for every thousand flights.

On time

87.3%

Arrivals under 15 minutes late, of 4,375 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.64%

National rate is 1.80%

Best carrier

SkyWest

92.5% on time across 2,153 flights

These figures cover 4,405 flights between June 2025 and May 2026. The median arrival is 11 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 SJC to LAX

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 92.5% of the time; Southwest Airlines manages 80.5%. Sample sizes sit next to every figure, because a two-point gap across 1,808 flights means less than a ten-point one.

On-time performance by carrier on SJC to LAX
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlinesthin sample	1	100.0%	—	0.00%	A+
SkyWest Airlines	2,153	92.5%	70 min	0.37%	A+
Delta Air Linesthin sample	360	91.7%	49 min	3.33%	A−
Frontier Airlinesthin sample	77	85.3%	67 min	2.60%	A
Southwest Airlines	1,808	80.5%	47 min	0.33%	B+
American Airlinesthin sample	6	66.7%	29 min	0.00%	C+

The spread between SkyWest and Southwest is 12 points, wide enough that it should decide the booking. On a hundred trips that is 12 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 16 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am679 flights95.7%
8am–11am807 flights92.8%
11am–2pm629 flights88.1%
2pm–5pm906 flights86.2%
5pm–8pm787 flights79.7%
8pm–5am597 flights81.4%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 95.7% of the time, against 79.7% for the evening window. That is 16 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

Twelve months, one bar each, drawn from the same 4,405 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.

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

December is the weak month at 82.1% on time, against 92.5% in January. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days.

Across the week, Tuesday is the strongest day at 90.8% on time and Friday the weakest at 83.8%. 7 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 43% of the 30,000 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
43%
Carrier
41%
National Airspace System
11%
Extreme weather
5%
Security
0%

43% 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 30,000 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 largest share of delay minutes, 41%, 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 12,000 of the 30,000 delay minutes reported here.

Cancellations are rare at 0.64%, 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

Badly late arrivals are rare here: only 3.3% land an hour or more behind schedule, against 8.2% 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 87.3% on time across 4,400 flights, within half 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 4,405 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: avoid the 5pm–8pm departure. It runs 79.7% on time against 95.7% for the 5am–8am slot, and that 16 points is the largest single thing you control here. SkyWest Airlines is the strongest operator if the fares are close.

Common questions

SJC to LAX questions

How often is SJC to LAX delayed?

About one flight in eight arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 12.7% of the 4,405 flights in this analysis, against 22.6% nationally. Delayed flights are late by roughly 55 minutes on average.

Which airline is most reliable on SJC to LAX?

SkyWest Airlines leads at 92.5% on time across 2,153 flights. Southwest Airlines is at the other end on 80.5%, a gap of 12 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 SJC to LAX?

The 5am–8am departure window is the strongest at 95.7% on time. The 5pm–8pm window is the weakest at 79.7%, 16 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 December delays on SJC to LAX?

December is the weakest month at 82.1% on time, compared with 92.5% in January. Across the year that is 10 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. SJC to LAX and LAX to SJC 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