Carrier route record

OOSEA→SJC

SkyWest Airlines · Seattle to San Jose

Flights: 1,562
Period: July 2025 to June 2026
Share of route: 36%
Carriers: 5

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

SkyWest on SEA to SJC earns an 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 77.6%. When something does go wrong the average delay runs about an hour. That rests on 1,562 flights. The strongest carrier on the route with a full sample, Alaska Airlines, flew 1,877 at 80.6% on time.

Set against the rest of the country, SkyWest's SEA to SJC record is 10 points better than the US average of 77.6%. That gap is worth roughly 104 fewer late arrivals for every thousand flights.

On time

88.0%

Arrivals under 15 minutes late, of 1,559 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

0.19%

National rate is 1.81%

Whole route

81.6%

Every carrier on SEA to SJC, 4,371 flights

These figures cover 1,562 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

SkyWest against every carrier on SEA to SJC

SkyWest flew 1,562 of the 4,371 flights on SEA to SJC, about 36% of it. Its 88.0% on time is 6 points better than the route as a whole, which runs 81.6%. Ranked by on-time rate it is number three of five carriers on the route, where the range runs from American at 100.0% to Southwest at 72.6%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Alaska Airlines arrives on time 80.6% of the time; Southwest Airlines manages 72.6%. Sample sizes sit next to every figure, because a two-point gap across 927 flights means less than a ten-point one.

On-time performance by carrier on SEA to SJC
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlinesthin sample	4	100.0%	—	0.00%	A+
United Airlinesthin sample	1	100.0%	—	0.00%	A+
SkyWest Airlines (this page)	1,562	88.0%	61 min	0.19%	A+
Alaska Airlines	1,877	80.6%	45 min	1.55%	B
Southwest Airlines	927	72.6%	45 min	0.32%	C+

Alaska leads Southwest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Flight by flight

SkyWest flight numbers on SEA to SJC

OO 378911:4584.5% · 349 flights

Departure window

When SkyWest runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,562 flights.

5am–8am—
8am–11am479 flights90.0%
11am–2pm332 flights88.0%
2pm–5pm323 flights87.0%
5pm–8pm99 flights81.8%
8pm–5am329 flights88.1%

Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 90.0% of the time, against 81.8% for the evening window. That is 8 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 479 flights scheduled in it.

Across the year

SkyWest on SEA to SJC through the year

Darker means more delays. Figures are on-time percentages.April best, February worst

February is the weak month at 80.6% on time, against 93.3% in April. 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. June was the busiest month here, with 150 flights.

Across the week, Wednesday is the strongest day at 91.0% on time and Friday the weakest at 85.1%. 6 points is a smaller lever than departure hour, but it is free.

Delay causes

Why SkyWest runs late on this route

One category carries most of the weight here. Carrier accounts for 57% of the 11,000 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.

Carrier
57%
Extreme weather
30%
National Airspace System
13%
Security
0%

Extreme weather accounts for 30% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 4.8 times the usual weather exposure. The split is drawn from 11,314 reported delay minutes.

The largest share of delay minutes, 57%, 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 6,418 of the 11,000 delay minutes reported here.

Cancellations are rare at 0.19%, 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 3.5% 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 696 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 89.5% on time across 1,563 flights, within 2 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 1,562 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 SkyWest on SEA to SJC

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 93.3% on time and February 80.6%, a swing of 13 points. If the dates move at all, move them out of February before you think about anything else. 1,559 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