Route profile
SEA→SAN
Flight reliability, delays and best times to fly from Seattle to San Diego, 1,050 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 72% of comparable major US routes (4,598 compared)
Calculated from 14,317 flights. How this is calculated
SEA → SAN arrives on time 78.5% of the time; the return trip, SAN → SEA, arrives on time 81.5% of the time, a 3.0-point gap between the two directions of the same city pair.
SEA → SAN spends 29.1 minutes on the ground on a 1,050-mile trip: 21.6 minutes from pushback to wheels-up at SEA and 7.5 minutes from touchdown to gate at SAN.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
This route holds up about the same all year, a steadier seasonal pattern than 96% of 3,357 comparable routes.
83.5% on time in its best month (April) against 74.3% in its worst (August).
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 3,357 in the comparison.
Why SEA → SAN flights are cancelled
July 2023 – July 2026
SEA → SAN cancelled 137 of 14,317 scheduled flights — about 1 in every 105. The reason filed most often was the airline, 75.2% of the cancellations coded on this route — about 1 in every 139 scheduled flights.
Share of cancellations
Of 137 cancelled departures carrying a reason code.
What each reason means
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
103 cancellations, 75.2% of the total.
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
31 cancellations, 22.6% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
3 cancellations, 2.2% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. With only one or two carriers on the route, the split mostly reflects how they file. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
137 coded cancellations were recorded on SEA → SAN; the section appears from 50.
When it goes wrong
July 2023 – July 2026
34 min late
against a median of 4 min early
Percentiles over 14,317 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SAN after arriving from SEA.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 41% | Likely to miss |
| 45 min | 21% | High risk |
| 60 min | 11% | Some risk |
| 90 min | 4.5% | Low risk |
| 120 min | 2.4% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.96% of the time and diverts 0.29% of the time, which a late arrival never shows up in.
Chance of missing is the share of 14,138 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 34 minutes late (90th-percentile gate arrival delay), over 14,317 operations.
Any other layover length: connection checker.
Best time to fly
SEA → SAN flights departing 5–9 AM arrived on time 86.5% of the time, against 72.8% for 6–9 PM departures, a gap of 13.7 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 86.3% on time from 206 flights
- 6 AM: 90.5% on time from 516 flights
- 7 AM: 86.3% on time from 1,994 flights
- 8 AM: 78.7% on time from 188 flights
- 9 AM: 81.0% on time from 1,693 flights
- 10 AM: 80.4% on time from 374 flights
- 11 AM: 78.0% on time from 1,861 flights
- 12 PM: 80.8% on time from 293 flights
- 1 PM: 80.0% on time from 425 flights
- 2 PM: 77.2% on time from 840 flights
- 3 PM: 81.2% on time from 1,120 flights
- 4 PM: 72.7% on time from 868 flights
- 5 PM: 66.8% on time from 562 flights
- 6 PM: 66.0% on time from 736 flights
- 7 PM: 74.6% on time from 1,678 flights
- 8 PM: 78.8% on time from 348 flights
- 9 PM: 73.0% on time from 615 flights
- 10 PM to 11 PM: too few flights to score
Why SEA → SAN runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for SEA → SAN. Only delays of 15 minutes or more are attributed.
How this route holds up in bad weather
July 2023 – July 2026
The harder-hit end is SAN, where the flight lands. Its figure counts departures from SAN, so it says more about how that airport copes than about this route. Bad weather cancels 3.5 times the normal rate at SAN against 1.9 times at SEA. Cancelled in bad weather against normal hours: SEA 1.5% against 0.8%, SAN 3.5% against 1.0%. Flights that did leave SAN in bad weather arrived on time 66.7% of the time, against 78.4% in normal hours.
Bad weather and normal hours at the airports
Scheduled departures, July 2023 – July 2026| Departures from | SEA | SAN |
|---|---|---|
| Cancelled in bad weather | 1.5% | 3.5% |
| Cancelled in normal hours | 0.8% | 1.0% |
| Arrived on time, bad weather | 75.4% | 66.7% |
| Arrived on time, normal hours | 79.3% | 78.4% |
| Departures in bad weather | 43,416 | 19,707 |
Of the carriers on this route, Delta Air Lines (1.1% cancelled against 1.6% for the other carriers at SEA) cancelled the fewest departures from SEA in bad weather and Alaska Airlines (1.8% cancelled against 1.2% for the other carriers at SEA) the most.
This route’s airlines in bad weather at SEA
All departures from SEA| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| Delta Air Lines | 9,020 | 1.1%below the others | 1.6% |
| Alaska Airlines | 20,261 | 1.8%above the others | 1.2% |
These are airport figures, not route figures: every scheduled departure from SEA and SAN, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from SEA on every route.
Weather source and limits. In full: SEA (airlines), SAN, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Alaska Airlines | 8,785 | 76.0% | 1.26% | -2 min | 4.3% |
| Delta Air Lines | 5,297 | 83.4% | 0.49% | -8 min | 5.0% |
Alaska Airlines flew 62.4% of the 14,082 flights listed.
Delta Air Lines arrived on time 7.4 percentage points more often than Alaska Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Friday the least, a gap of 9.3 percentage points.
By month
- Jan: 80.3%
- Feb: 79.5%
- Mar: 78.9%
- Apr: 83.5%
- May: 80.4%
- Jun: 75.1%
- Jul: 74.7%
- Aug: 74.3%
- Sep: 82.0%
- Oct: 79.7%
- Nov: 78.9%
- Dec: 77.8%
August is historically the weakest month and April the strongest, a spread of 9.2 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 81.0% from 421 flights
- August 2023: 75.0% from 429 flights
- September 2023: 82.9% from 405 flights
- October 2023: 88.5% from 393 flights
- November 2023: 83.6% from 374 flights
- December 2023: 87.9% from 383 flights
- January 2024: 76.8% from 351 flights
- February 2024: 81.5% from 336 flights
- March 2024: 79.8% from 374 flights
- April 2024: 80.7% from 368 flights
- May 2024: 80.8% from 396 flights
- June 2024: 74.9% from 410 flights
- July 2024: 77.8% from 438 flights
- August 2024: 75.6% from 436 flights
- September 2024: 81.4% from 422 flights
- October 2024: 74.7% from 387 flights
- November 2024: 80.7% from 353 flights
- December 2024: 76.2% from 390 flights
- January 2025: 83.9% from 345 flights
- February 2025: 75.0% from 306 flights
- March 2025: 80.9% from 354 flights
- April 2025: 81.1% from 366 flights
- May 2025: 77.1% from 412 flights
- June 2025: 77.4% from 427 flights
- July 2025: 76.0% from 446 flights
- August 2025: 72.3% from 426 flights
- September 2025: 81.7% from 387 flights
- October 2025: 75.4% from 348 flights
- November 2025: 71.2% from 319 flights
- December 2025: 68.4% from 358 flights
- January 2026: 80.0% from 334 flights
- February 2026: 81.6% from 306 flights
- March 2026: 76.1% from 388 flights
- April 2026: 88.0% from 409 flights
- May 2026: 83.2% from 427 flights
- June 2026: 73.2% from 436 flights
- July 2026: 64.7% from 457 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 76.2% against 78.3% in the 12 months before — declining by 2.1 percentage points.
Data and methodology
Calculated by FlyerIntel from 14,317 SEA → SAN flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed