Route reliability record

LAX→SJC

Los Angeles to San Jose

Flights: 4,429
Period: July 2025 to June 2026
Distance: 308 mi
Carriers: 6

This route earns a A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs roughly 50 minutes. That rests on 4,429 flights, of which SkyWest Airlines flew 2,049 at 91.4% on time.

SkyWest Airlines is the most reliable of the three carriers covered here at 91.4% on time across 2,049 flights.

On time

86.6%

Arrivals under 15 minutes late, of 4,393 completed flights

Avg delay

52 min

Across delayed arrivals only, not all flights

Cancelled

0.79%

National rate is 1.81%

Best carrier

SkyWest

91.4% on time across 2,049 flights

These figures cover 4,429 flights between July 2025 and June 2026. The median arrival is 12 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 LAX to SJC

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 91.4% of the time; Southwest Airlines manages 81.5%. Sample sizes sit next to every figure, because a two-point gap across 1,822 flights means less than a ten-point one.

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	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+

SkyWest leads Southwest by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

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 17 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am590 flights94.3%
8am–11am681 flights92.7%
11am–2pm908 flights90.5%
2pm–5pm719 flights86.7%
5pm–8pm887 flights79.8%
8pm–5am644 flights76.9%

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 94.3% of the time, against 76.9% for the overnight window. That is 17 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 908 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 13 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.August best, June worst

June is the worst month at 79.0% on time, 13 points below August, the best at 92.1%. 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. September was the busiest month here, with 424 flights.

Across the week, Tuesday is the strongest day at 90.5% on time and Sunday the weakest at 81.8%. 9 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 48% of the 31,000 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
48%
Carrier
42%
National Airspace System
5%
Extreme weather
5%
Security
0%

48% 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 31,000 reported delay minutes here, that single category outweighs weather by 10 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 30,564 reported delay minutes.

The largest share of delay minutes, 42%, 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 13,000 of the 31,000 delay minutes reported here.

Cancellations are rare at 0.79%, 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

Badly late arrivals are rare here: only 3.7% 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 86.6% on time across 4,433 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 4,429 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. August runs 92.1% on time and June 79.0%, a swing of 13 points. If the dates move at all, move them out of June before you think about anything else. 4,393 completed flights over 12 months sit behind that.

Common questions

LAX to SJC questions

How often is LAX to SJC delayed?

About one flight in seven arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.4% of the 4,429 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 50 minutes on average.

Which airline is most reliable on LAX to SJC?

SkyWest Airlines leads at 91.4% on time across 2,049 flights. Southwest Airlines is at the other end on 81.5%, a gap of 10 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 LAX to SJC?

The 5am–8am departure window is the strongest at 94.3% on time. The 8pm–5am window is the weakest at 76.9%, 17 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 LAX to SJC?

June is the weakest month at 79.0% on time, compared with 92.1% in August. Across the year that is 13 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. LAX to SJC and SJC to LAX 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