Best Time to Fly SFO to SEA: On-Time Stats by Hour & Airline
San Francisco International → Seattle/Tacoma International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 73.2% of San Francisco (SFO) to Seattle (SEA) flights arrived on time (6,797 scheduled flights). That is 4.4 points below the national average of 77.6%.
Delta Air Lines was the most punctual of the 4 airlines on the route at 81.3%, while Alaska Airlines trailed at 69.7%.
January has been the best month (86% on time) and Thursday the weakest day of the week (71%).
1.1% of flights were cancelled, versus 1.8% nationally.
SFO to SEA 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 | 81.3% | 79 min | 1.7% | 955 |
| United Airlines | 75.5% | 58 min | 0.4% | 2,053 |
| SkyWest Airlines | 70.3% | 51 min | 1.1% | 1,073 |
| Alaska Airlines | 69.7% | 54 min | 1.3% | 2,713 |
| Southwest Airlines | Limited data | 3 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SFO to SEA
On-time arrival % by scheduled departure hour (local time), 13,738 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 96.4% | 0.3% | 386 |
| 6am–7am | 92.5% | 1.0% | 1,022 |
| 7am–8am | 89.0% | 1.6% | 493 |
| 8am–9am | 56.7% | 1.0% | 597 |
| 9am–10am | 81.5% | 0.7% | 978 |
| 10am–11am | 68.2% | 2.3% | 1,153 |
| 11am–12pm | 78.5% | 2.9% | 617 |
| 12pm–1pm | 68.2% | 1.9% | 542 |
| 1pm–2pm | 80.2% | 0.3% | 1,100 |
| 2pm–3pm | 69.9% | 1.1% | 945 |
| 3pm–4pm | 65.6% | 1.1% | 94 |
| 4pm–5pm | 74.2% | 0.7% | 1,747 |
| 5pm–6pm | 69.3% | 0.2% | 421 |
| 6pm–7pm | 72.6% | 0.5% | 1,108 |
| 7pm–8pm | 62.7% | 1.0% | 672 |
| 8pm–9pm | 70.8% | 0.8% | 969 |
| 9pm–10pm | 67.0% | 1.1% | 377 |
| 10pm–11pm | 73.0% | 0.6% | 515 |
| 11pm–12am | Limited data | 2 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SFO to SEA
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) | 86.3% | +9.1 pts | 0.0% | 256 |
| Christmas & New Year (Dec 20 - Jan 3) | 65.8% | -11.4 pts | 1.0% | 499 |
| Summer peak (Jun 15 - Aug 15) | 65.4% | -11.8 pts | 1.1% | 2,598 |
| All other days | 77.2% | — | 1.0% | 10,385 |
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).