Carrier route record
ASSAN→SEA
Alaska Airlines · San Diego to Seattle
- Flights
- 2,763
- 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 SAN to SEA lands a B, level with the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 2,763 flights, with a median arrival 6 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Alaska on SAN to SEA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.8%
Arrivals under 15 minutes late, of 2,705 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
2.10%
National rate is 1.81%
Whole route
80.8%
Every carrier on SAN to SEA, 4,582 flights
These figures cover 2,763 flights between July 2025 and June 2026. The median arrival is 6 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 SAN to SEA
Alaska flew 2,763 of the 4,582 flights on SAN to SEA, most of the route. Its 77.8% on time is 3 points worse than the route as a whole, which runs 80.8%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Delta at 87.3% to SkyWest at 0.0%. 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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,700 | 87.3% | 76 min | 1.06% | A |
| Alaska Airlines (this page) | 2,763 | 77.8% | 61 min | 2.10% | B |
| Southwest Airlinesthin sample | 118 | 58.1% | 44 min | 0.00% | D+ |
| SkyWest Airlinesthin sample | 1 | 0.0% | 28 min | 0.00% | F+ |
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 17 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–8am489 flights89.0%
- 8am–11am422 flights79.0%
- 11am–2pm496 flights76.6%
- 2pm–5pm530 flights75.0%
- 5pm–8pm598 flights71.6%
- 8pm–5am228 flights77.6%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.0% of the time, against 71.6% for the evening 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 5pm–8pm window is the busiest, with 598 flights scheduled in it.
Across the year
Alaska on SAN to SEA through the year
August is the worst month at 62.4% on time, 29 points below February, the best at 91.2%. 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. July was the busiest month here, with 299 flights.
Across the week, Tuesday is the strongest day at 84.9% on time and Friday the weakest at 68.1%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Alaska runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 37,000 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.
- 52%Late-arriving aircraft
- 31%Carrier
- 16%National Airspace System
- 1%Security
- 1%Extreme weather
52% 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 37,000 reported delay minutes here, that single category outweighs weather by 52 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 36,728 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 89.0% on time here.
Cancellations sit at 2.10% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
6.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
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 75.0% on time across 2,765 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 2,763 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 SAN to SEA
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 91.2% on time and August 62.4%, a swing of 29 points. If the dates move at all, move them out of August before you think about anything else. 2,705 completed flights over 12 months sit behind that.
Related
Where to go next
- SAN to SEA, every carrier
- Alaska on SEA to SAN, the return leg
- Delta Air Lines on SAN to SEA87.3%
- Southwest Airlines on SAN to SEA58.1%
- Alaska Airlines network-wide record
- San Diego International (SAN) delay statistics
- Seattle-Tacoma International (SEA) 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.