Carrier route record
ASSEA→SAN
Alaska Airlines · Seattle to San Diego
- Flights
- 2,765
- Period
- July 2025 to June 2026
- Share of route
- 60%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on SEA to SAN sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land roughly 45 minutes behind schedule. That rests on 2,765 flights, with a median arrival 2 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Alaska on SEA to SAN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 2,716 completed flights
Avg delay
44 min
Across delayed arrivals only, not all flights
Cancelled
1.45%
National rate is 1.81%
Whole route
77.3%
Every carrier on SEA to SAN, 4,584 flights
These figures cover 2,765 flights between July 2025 and June 2026. The median arrival is 2 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
Alaska against every carrier on SEA to SAN
Alaska flew 2,765 of the 4,584 flights on SEA to SAN, most of the route. Its 75.0% on time is 2 points worse than the route as a whole, which runs 77.3%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from SkyWest at 100.0% to Southwest at 55.9%. 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Delta Air Lines | 1,700 | 82.6% | 53 min | 0.94% | B+ |
| Alaska Airlines (this page) | 2,765 | 75.0% | 44 min | 1.45% | B |
| Southwest Airlinesthin sample | 118 | 55.9% | 41 min | 0.00% | D+ |
Departure window
When Alaska runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 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–8am355 flights90.5%
- 8am–11am402 flights77.4%
- 11am–2pm479 flights72.2%
- 2pm–5pm563 flights76.4%
- 5pm–8pm552 flights61.2%
- 8pm–5am414 flights79.6%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 61.2% on time, against 90.5% 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 2pm–5pm window is the busiest, with 563 flights scheduled in it.
Across the year
Alaska on SEA to SAN through the year
December is the weak month at 65.2% on time, against 91.0% 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. July was the busiest month here, with 299 flights.
Across the week, Wednesday is the strongest day at 80.7% on time and Sunday the weakest at 67.2%. 14 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Alaska runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 30,000 reported delay minutes.
- 33%Late-arriving aircraft
- 33%Carrier
- 32%National Airspace System
- 2%Extreme weather
- 0%Security
32% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 9,516 minutes out of 30,000, against a national NAS share of 21%. The split is drawn from 29,683 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 90.5% on time here.
Cancellations sit at 1.45% against a national 1.81%, which is ordinary. Diversions add another 0.33%.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 4.7% 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.
The 1,050 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 77.8% on time across 2,763 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 2,765 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 Alaska on SEA to SAN
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 91.0% on time and December 65.2%, a swing of 26 points. If the dates move at all, move them out of December before you think about anything else. 2,716 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to SAN, every carrier
- Alaska on SAN to SEA, the return leg
- Delta Air Lines on SEA to SAN82.6%
- Southwest Airlines on SEA to SAN55.9%
- Alaska Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- San Diego International (SAN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.