Seattle (SEA) to Boise (BOI): On-Time Performance
Data through July 2026
When you fly SEA to BOI matters as much as anything else about the booking: the route swung from 92% on-time in October 2025 to just 70% in February 2025. Across the full period the route averages 84% on-time against a national 78%.
- On-time
- 84%
- arrived <15 min late
- Avg delay
- 9 min
- completed flights
- Cancelled
- 0.3%
- Flights/day
- 11
- last 12 months
- Duration
- 1h 31m
- scheduled
- Distance
- 399 mi
Best airline from SEA to BOI
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| SkyWest Airlinesmost reliable | 86% | 9 min | 0.2% | 6,349 |
| Alaska Airlines | 76% | 12 min | 0.5% | 1,629 |
Monthly on-time trend
Best time to fly from SEA to BOI
Aim for departures around 8 a.m. (92% on-time); avoid 8 p.m. departures (74%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 82% | 9 min |
| Tuesday | 87% | 7 min |
| Wednesday | 84% | 9 min |
| Thursday | 80% | 12 min |
| Friday | 83% | 9 min |
| Saturdaybest | 87% | 8 min |
| Sunday | 81% | 11 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft23%
- Airline operations47%
- National airspace system13%
- Weather16%
- Security1%
Frequently asked questions
- How often are flights from SEA to BOI delayed?
- 17% of SEA–BOI flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 9 minutes.
- Which airline is most reliable from SEA to BOI?
- SkyWest Airlines has the best on-time record on this route at 86%, based on 6,349 flights. 2 airlines flew SEA–BOI frequently enough to compare in this period.
- What is the best time of day to fly from SEA to BOI?
- Departures around 8 a.m. have the best record (92% on-time), while departures around 8 p.m. have the worst (74%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SEA to BOI?
- The scheduled SEA–BOI flight time averages 1h 31m over 399 miles. Actual arrival times vary — flights on this route land 15+ minutes late 17% of the time.
- How often are SEA to BOI flights cancelled?
- 0.3% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from SEA to BOI?
- February 2025 was the roughest month in this dataset, with only 70% of arrivals on time. The best was October 2025 at 92%. If your dates are flexible, that 22-point gap is worth planning around.
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Based on 7,979 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.