Best Time to Fly BOS to SEA: On-Time Stats by Hour & Airline
Logan International → Seattle/Tacoma International
Data through July 2026 · Last updated October 18, 2026
2,504 flights were scheduled from Boston (BOS) to Seattle (SEA) in the last 12 months, and 72.4% of those that flew arrived on time, 5.2 points below the US average of 77.6%.
JetBlue was the most punctual of the 3 airlines on the route at 78.6%, while Alaska Airlines trailed at 71.0%.
September has been the best month (86% on time) and Thursday the weakest day of the week (71%).
1.3% of flights were cancelled, versus 1.8% nationally.
BOS 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 |
|---|---|---|---|---|
| JetBlue | 78.6% | 71 min | 1.2% | 247 |
| Delta Air Lines | 72.6% | 56 min | 1.4% | 1,035 |
| Alaska Airlines | 71.0% | 50 min | 1.1% | 1,222 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly BOS to SEA
On-time arrival % by scheduled departure hour (local time), 5,055 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | Limited data | 16 | |
| 7am–8am | 80.4% | 0.9% | 1,742 |
| 8am–9am | 73.3% | 0.0% | 30 |
| 9am–10am | 74.3% | 0.6% | 471 |
| 10am–11am | 76.9% | 1.3% | 158 |
| 11am–12pm | 82.4% | 0.7% | 454 |
| 3pm–4pm | 72.6% | 0.0% | 85 |
| 4pm–5pm | 75.4% | 0.8% | 262 |
| 5pm–6pm | 77.1% | 0.8% | 396 |
| 6pm–7pm | 64.3% | 1.5% | 974 |
| 7pm–8pm | 65.4% | 1.9% | 466 |
| 8pm–9pm | Limited data | 1 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on BOS 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) | 88.6% | +11.1 pts | 0.0% | 79 |
| Christmas & New Year (Dec 20 - Jan 3) | 53.5% | -24.0 pts | 0.6% | 162 |
| Summer peak (Jun 15 - Aug 15) | 68.0% | -9.5 pts | 1.5% | 1,151 |
| All other days | 77.5% | — | 1.0% | 3,663 |
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).