PlainFlights

Route · BOI → SEA · 2020–2025 BTS data

Boise to Seattle

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), BOI to SEA (Boise to Seattle) ranks #221 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

86.9%
On-time
+7.9 pts
vs US avg
62 min
Delay when late
24,617
Flights
#221 of 4927
Corpus placement

Cancelled

0.3%

Best Month

Mar 2024 91%

Worst Month

Jan 2024 70%

Distance

399 mi

Carriers

8

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 238 30 0 2 AS,OO
Nov 2025 252 35 3 0 OO,AS
Oct 2025 301 45 1 0 AS,OO
Sep 2025 330 52 2 0 OO,AS
Aug 2025 349 64 0 0 OO,AS
Jul 2025 362 57 1 0 AS,OO
Jun 2025 339 58 1 0 AS,OO
May 2025 316 44 0 0 AS,OO
Apr 2025 344 50 0 0 OO,AS
Mar 2025 334 43 1 2 AS,OO
Feb 2025 284 77 3 0 AS,OO
Jan 2025 310 55 1 2 AS,OO
Dec 2024 260 47 4 1 AS,OO
Nov 2024 262 33 0 0 OO,AS
Oct 2024 304 35 0 0 AS,OO
Sep 2024 280 56 0 2 OO,AS
Aug 2024 310 83 0 0 AS,OO
Jul 2024 312 63 1 0 AS,DL,OO
Jun 2024 323 69 0 0 AS,OO
May 2024 362 61 0 0 AS,OO
Apr 2024 331 44 0 0 AS,OO
Mar 2024 351 30 1 0 AS,OO
Feb 2024 312 31 0 1 AS,OO
Jan 2024 304 92 2 0 AS,OO

BOI–SEA seasonal on-time pattern

Best: March (90.8%) · weakest: January (83.0%)

82%84%86%88%90%92% JanFebMarAprMayJunJulAugSepOctNovDec 83.4%

Strongest calendar month

March

90.8% on-time · ~363 flights/mo

Busiest calendar month

October

~368 flights/mo avg

Weakest calendar month

January

83.0% on-time · ~329 flights/mo

Cancellation Rate

0.3%

21 of 7,470 flights

Diversion Rate

0.1%

10 of 7,470 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

BOI - Boise

Full on-time, delay-cause, and seasonal performance for Boise, ID.

BOI on-time profile

SEA - Seattle

Full on-time, delay-cause, and seasonal performance for Seattle, WA.

SEA on-time profile

Compare the two airports

See BOI and SEA side by side on delays, cancellations, and reliability.

Compare BOI vs SEA

Origin-hub reliability standing

Among BOI's stronger departures

BOI → SEA posts a 86.9% on-time rate, landing in the ≥85% band with 10 of 19 BTS-tracked routes leaving Boise. The same hub also shows 9 mid-band and 0 challenged departures · fleet-wide on-time rank #642 of 4927 (highest on-time = #1).

What the Data Says About BOI to SEA

Boise to Seattle (BOI to SEA) is one of the more dependable pairings in the BTS On-Time Performance dataset: a 86.9% on-time rate across 24,617 flights, with delays that do happen averaging 61.9 minutes. The corridor runs roughly 399 miles and is served by 8 carriers. Over the most recent 24 months, 21 of 7,470 flights were cancelled (0.3%) and 10 diverted (0.1%).

The monthly split is wide on this route: Mar 2024 posted the strongest performance at 91% on-time, while Jan 2024 came in at just 70% - a 22-point swing worth factoring into travel timing.

On the multi-year calendar, BOI–SEA peaks in March at 90.8% on-time while October carries the heaviest traffic (~368 flights per month) ; the softest month is January at 83.0%, a 7.8-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does BOI to SEA rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, BOI to SEA ranks #221 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from BOI to SEA? ▼
Flights from Boise to Seattle have a 86.9% on-time rate based on 24,617 flights. The average delay is 61.9 minutes. The best recent month was Mar 2024 with 91% on-time.
What is the cancellation rate for BOI to SEA? ▼
Over the last 24 months, 0.3% of flights on this route were cancelled (21 of 7,470 flights) and 0.1% were diverted.
How far is the flight from BOI to SEA? ▼
The flight distance from Boise (BOI) to Seattle (SEA) is approximately 399 miles. This route is served by 8 carriers.
When is the best time to fly from BOI to SEA? ▼
The best recent month for on-time performance was Mar 2024 (91% on-time). The worst was Jan 2024 (70% on-time). Consider booking during months with historically better performance.

Airports on this route

BOI Airport

Boise
SEA Airport

Seattle
Data source

Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.

Read our methodology - how this data is sourced, computed, and verified.

Using BOI–SEA data

BOI–SEA runs 7.9 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare BOI and SEA airport profiles: delay causes and top routes differ even on the same corridor. BOI airport
  • If your dates flex, March (90.8% on-time) beats January (83.0%) on this corridor. Seasonal chart
  • 4 other routes post a similar 86.9% on-time rate; compare before you commit to this pairing. Similar routes

On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.