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Route · SEA → BOI · 2020–2025 BTS data

Seattle to Boise

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), SEA to BOI (Seattle to Boise) ranks #207 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

86%
On-time
+7 pts
vs US avg
59 min
Delay when late
25,171
Flights
#207 of 4927
Corpus placement

Cancelled

0.2%

Best Month

Oct 2025 92%

Worst Month

Feb 2025 70%

Distance

399 mi

Carriers

8

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 266 39 0 0 AS,OO
Nov 2025 282 37 3 1 OO,AS
Oct 2025 333 28 0 0 AS,OO
Sep 2025 334 46 0 0 OO,AS
Aug 2025 370 74 0 0 OO,AS
Jul 2025 394 79 1 0 AS,OO
Jun 2025 368 87 1 0 AS,OO
May 2025 334 48 0 0 AS,OO
Apr 2025 344 56 0 0 OO,AS
Mar 2025 334 57 1 0 AS,OO
Feb 2025 284 85 2 0 AS,OO
Jan 2025 311 54 1 0 AS,OO
Dec 2024 259 49 3 1 AS,OO
Nov 2024 262 25 0 0 OO,AS
Oct 2024 306 32 1 0 AS,OO
Sep 2024 280 67 0 0 OO,AS
Aug 2024 310 64 0 0 AS,OO
Jul 2024 312 55 1 0 AS,DL,OO
Jun 2024 323 78 0 0 AS,OO
May 2024 362 73 0 0 AS,OO
Apr 2024 331 38 0 0 AS,OO
Mar 2024 352 32 1 0 AS,OO
Feb 2024 312 33 0 0 AS,OO
Jan 2024 307 76 2 0 AS,OO

SEA–BOI seasonal on-time pattern

Best: October (90.5%) · weakest: December (79.7%)

75%80%85%90%95% JanFebMarAprMayJunJulAugSepOctNovDec 79.7%

Strongest calendar month

October

90.5% on-time · ~379 flights/mo

Busiest calendar month

October

~379 flights/mo avg

Weakest calendar month

December

79.7% on-time · ~310 flights/mo

Cancellation Rate

0.2%

17 of 7,670 flights

Diversion Rate

0.0%

2 of 7,670 flights

Explore origin & destination

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

SEA - Seattle

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

SEA on-time profile

BOI - Boise

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

BOI on-time profile

Compare the two airports

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

Compare SEA vs BOI

Origin-hub reliability standing

Among SEA's stronger departures

SEA → BOI posts a 86% on-time rate, landing in the ≥85% band with 25 of 89 BTS-tracked routes leaving Seattle. The same hub also shows 63 mid-band and 1 challenged departures · fleet-wide on-time rank #919 of 4927 (highest on-time = #1).

What the Data Says About SEA to BOI

Seattle to Boise (SEA to BOI) is one of the more dependable pairings in the BTS On-Time Performance dataset: a 86% on-time rate across 25,171 flights, with delays that do happen averaging 58.6 minutes. The corridor runs roughly 399 miles and is served by 8 carriers. Over the most recent 24 months, 17 of 7,670 flights were cancelled (0.2%) and 2 diverted (0.0%).

The monthly split is wide on this route: Oct 2025 posted the strongest performance at 92% on-time, while Feb 2025 came in at just 70% - a 22-point swing worth factoring into travel timing.

On the multi-year calendar, SEA–BOI peaks in October at 90.5% on-time ; the softest month is December at 79.7%, a 10.8-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does SEA to BOI rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, SEA to BOI ranks #207 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 SEA to BOI? ▼
Flights from Seattle to Boise have a 86% on-time rate based on 25,171 flights. The average delay is 58.6 minutes. The best recent month was Oct 2025 with 92% on-time.
What is the cancellation rate for SEA to BOI? ▼
Over the last 24 months, 0.2% of flights on this route were cancelled (17 of 7,670 flights) and 0.0% were diverted.
How far is the flight from SEA to BOI? ▼
The flight distance from Seattle (SEA) to Boise (BOI) is approximately 399 miles. This route is served by 8 carriers.
When is the best time to fly from SEA to BOI? ▼
The best recent month for on-time performance was Oct 2025 (92% on-time). The worst was Feb 2025 (70% on-time). Consider booking during months with historically better performance.

Airports on this route

SEA Airport

Seattle
BOI Airport

Boise
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 SEA–BOI data

SEA–BOI runs 7 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare SEA and BOI airport profiles: delay causes and top routes differ even on the same corridor. SEA airport
  • If your dates flex, October (90.5% on-time) beats December (79.7%) on this corridor. Seasonal chart
  • 4 other routes post a similar 86% 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.