Best Time to Fly SEA to SAN: On-Time Stats by Hour & Airline
Seattle/Tacoma International → San Diego International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 76.2% of Seattle (SEA) to San Diego (SAN) flights arrived on time (4,595 scheduled flights). That is 1.4 points below the national average of 77.6%.
Delta Air Lines was the most punctual of the 3 airlines on the route at 82.1%, while Southwest Airlines trailed at 51.7%.
April has been the best month (85% on time) and Sunday the weakest day of the week (71%).
1.0% of flights were cancelled, versus 1.8% nationally.
SEA to SAN on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Delta Air Lines | 82.1% | 53 min | 1.0% | 1,704 |
| Alaska Airlines | 73.9% | 44 min | 1.1% | 2,741 |
| Southwest Airlines | 51.7% | 42 min | 0.0% | 149 |
| SkyWest Airlines | Limited data | 1 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SEA to SAN
On-time arrival % by scheduled departure hour (local time), 9,239 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 75.0% | 0.0% | 44 |
| 6am–7am | 90.4% | 1.0% | 296 |
| 7am–8am | 87.7% | 0.9% | 1,296 |
| 8am–9am | 80.7% | 0.0% | 31 |
| 9am–10am | 80.0% | 0.7% | 1,075 |
| 10am–11am | 80.4% | 0.5% | 374 |
| 11am–12pm | 76.2% | 0.8% | 1,123 |
| 12pm–1pm | 82.0% | 0.4% | 230 |
| 1pm–2pm | 78.7% | 0.3% | 386 |
| 2pm–3pm | 73.7% | 1.2% | 490 |
| 3pm–4pm | 80.5% | 0.5% | 738 |
| 4pm–5pm | 70.3% | 1.5% | 584 |
| 5pm–6pm | 61.7% | 0.5% | 386 |
| 6pm–7pm | 62.6% | 1.1% | 462 |
| 7pm–8pm | 73.1% | 0.7% | 1,156 |
| 8pm–9pm | 74.9% | 2.1% | 193 |
| 9pm–10pm | 74.9% | 1.9% | 375 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SEA to SAN
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 82.0% | +2.7 pts | 0.0% | 157 |
| Christmas & New Year (Dec 20 - Jan 3) | 60.4% | -19.0 pts | 2.0% | 344 |
| Summer peak (Jun 15 - Aug 15) | 71.9% | -7.4 pts | 1.5% | 1,799 |
| All other days | 79.3% | — | 0.7% | 6,939 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).