BOI to SEA flight delays
BOI SEA Boise Air Terminal/Gowen to Seattle Tacoma · 399 miles
11,537 flights were scheduled from BOI to SEA over July 2023 through June 2026. Of the 11,487 that made the trip, 84.4% reached the gate less than 15 minutes behind schedule. These are arrival figures: “on time” means the flight reached the gate less than 15 minutes behind schedule. Arrivals are what decide whether you make the connection, so route and airline pages are scored on them rather than on pushback.
Data through June 2026 · Bureau of Transportation Statistics
The route in brief
- Flights in the window
- 11,537
- Arrived on time
- 84.4%
- Cancelled
- 0.3%
- Scheduled distance
- 399 miles
Cancellations are counted against everything scheduled. Diverted flights are counted with them rather than as very late arrivals, which is why the on-time share and the cancellation rate do not add up to everything that happened.
Airline by airline
Airlines with at least 100 flights on BOI–SEA, busiest first. Same route, same weather, same air traffic — which makes this the fairest comparison on the site.
| Airline | Arrived on time | Typical delay | Cancelled | Flights |
|---|---|---|---|---|
| SkyWest Airlines | 84.9% | 55 min | 0.2% | 9,289 |
| Alaska Airlines | 82.1% | 49 min | 0.6% | 2,214 |
Month by month
January was the month to avoid on BOI–SEA: 78.4% of flights arrived on time, against 89% in March. Each bar pools three years of that calendar month.
| Month | Share flights that arrived on time | Flights |
|---|---|---|
| January | 78.4% | 906 |
| February | 85.4% | 889 |
| March | 89% | 1,054 |
| April | 87.2% | 1,031 |
| May | 84.6% | 1,044 |
| June | 81.1% | 974 |
| July | 84.2% | 1,032 |
| August | 79.1% | 1,009 |
| September | 83.7% | 959 |
| October | 86.8% | 998 |
| November | 87.3% | 870 |
| December | 85.8% | 771 |
Both ends of the route
A route’s record is built out of two airports’ habits. The hour-by-hour grid for each is on its own page.
BOI to SEA in one number
BOI → SEA
When a flight on this route was late, it was late by about 54 min.
Questions about BOI to SEA
- Which airline is most reliable from BOI to SEA?
- SkyWest Airlines — its flights on this pairing arrived on time 84.9% of the time, with 9,289 scheduled. Alaska Airlines came in at 82.1% over 2,214 scheduled. Airlines with fewer than 100 flights on the route are not rated.
- What is the worst month to fly BOI to SEA?
- January, at 78.4% of arrivals on time, with 906 flights scheduled. March was the best of the year at 89%.
- How late are BOI–SEA flights when they are late?
- 54 min on average, counting only the flights that arrived 15 minutes or more behind schedule. The on-time flights are left out of that average on purpose — mixing them in would flatter it.
- How often is the BOI to SEA flight cancelled?
- 0.3% of scheduled flights on this route were cancelled, July 2023 through June 2026. Diverted flights are counted with the cancellations rather than as late arrivals.
- Are these departure or arrival numbers?
- Arrival. A flight counts as on time here if it reached the gate at SEA less than 15 minutes behind schedule. Airport pages score departures instead, because that is the number you can act on when you pick a booking time.