Seattle (SEA) to San Diego (SAN): On-Time Performance
Data through May 2026
When you fly SEA to SAN matters as much as anything else about the booking: the route swung from 88% on-time in April 2026 to just 68% in December 2025. Across the full period the route averages 78% on-time against a national 78%. Morning departures also hold up better than evening ones (82% vs 70%), which matters most in the rough months.
- On-time
- 78%
- arrived <15 min late
- Avg delay
- 12 min
- completed flights
- Cancelled
- 0.9%
- Flights/day
- 13
- last 12 months
- Duration
- 2h 51m
- scheduled
- Distance
- 1,050 mi
Best airline from SEA to SAN
3 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Delta Air Linesmost reliable | 82% | 11 min | 0.6% | 3,396 |
| Alaska Airlines | 76% | 12 min | 1.1% | 5,675 |
| Southwest Airlines | 59% | 20 min | 0.0% | 88 |
Monthly on-time trend
Best time to fly from SEA to SAN
Aim for departures around 6 a.m. (90% on-time); avoid 6 p.m. departures (63%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 78% | 12 min |
| Tuesdaybest | 84% | 8 min |
| Wednesday | 80% | 10 min |
| Thursday | 76% | 13 min |
| Friday | 75% | 14 min |
| Saturday | 79% | 12 min |
| Sunday | 73% | 14 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft28%
- Airline operations38%
- National airspace system30%
- Weather4%
Frequently asked questions
- How often are flights from SEA to SAN delayed?
- 22% of SEA–SAN flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 12 minutes.
- Which airline is most reliable from SEA to SAN?
- Delta Air Lines has the best on-time record on this route at 82%, based on 3,396 flights. 3 airlines flew SEA–SAN frequently enough to compare in this period.
- What is the best time of day to fly from SEA to SAN?
- Departures around 6 a.m. have the best record (90% on-time), while departures around 6 p.m. have the worst (63%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SEA to SAN?
- The scheduled SEA–SAN flight time averages 2h 51m over 1,050 miles. Actual arrival times vary — flights on this route land 15+ minutes late 22% of the time.
- How often are SEA to SAN flights cancelled?
- 0.9% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from SEA to SAN?
- December 2025 was the roughest month in this dataset, with only 68% of arrivals on time. The best was April 2026 at 88%. If your dates are flexible, that 20-point gap is worth planning around.
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Based on 9,194 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.