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Route · SEA → BLI · 2020–2025 BTS data

Seattle to Bellingham

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), SEA to BLI (Seattle to Bellingham) ranks #2089 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

85.1%
On-time
+6.1 pts
vs US avg
51 min
Delay when late
5,958
Flights
#2089 of 4927
Corpus placement

Cancelled

1.4%

Best Month

Dec 2024 94%

Worst Month

Jun 2025 71%

Distance

93 mi

Carriers

2

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 124 29 3 0 OO
Nov 2025 97 13 10 0 OO
Oct 2025 116 16 2 0 OO
Sep 2025 120 18 0 0 OO
Aug 2025 124 23 1 0 OO
Jul 2025 124 23 1 0 OO
Jun 2025 119 35 0 0 OO
May 2025 119 25 0 0 OO
Apr 2025 96 14 0 0 OO
Mar 2025 103 27 1 0 OO
Feb 2025 105 30 3 0 OO
Jan 2025 113 16 5 0 OO
Dec 2024 82 5 4 0 OO
Nov 2024 83 10 1 0 OO
Oct 2024 88 14 0 0 OO
Sep 2024 85 24 1 0 OO
Aug 2024 88 24 0 0 OO
Jul 2024 88 22 0 0 OO
Jun 2024 85 20 0 0 OO
May 2024 83 11 0 0 OO
Apr 2024 83 15 0 0 OO
Mar 2024 80 8 0 0 OO
Feb 2024 58 5 0 0 OO
Jan 2024 62 8 0 0 OO

SEA–BLI seasonal on-time pattern

Best: October (89.6%) · weakest: June (80.0%)

75%80%85%90%95% JanFebMarAprMayJunJulAugSepOctNovDec 81.9%

Strongest calendar month

October

89.6% on-time · ~112 flights/mo

Busiest calendar month

July

~115 flights/mo avg

Weakest calendar month

June

80.0% on-time · ~104 flights/mo

Cancellation Rate

1.4%

32 of 2,325 flights

Diversion Rate

0.0%

0 of 2,325 flights

Origin-hub reliability standing

Among SEA's stronger departures

SEA → BLI posts a 85.1% 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 #1194 of 4927 (highest on-time = #1).

What the Data Says About SEA to BLI

Seattle to Bellingham (SEA to BLI) is one of the more dependable pairings in the BTS On-Time Performance dataset: a 85.1% on-time rate across 5,958 flights, with delays that do happen averaging 51.4 minutes. The corridor runs roughly 93 miles and is served by 2 carriers. Over the most recent 24 months, 32 of 2,325 flights were cancelled (1.4%) and 0 diverted (0.0%).

The monthly split is wide on this route: Dec 2024 posted the strongest performance at 94% on-time, while Jun 2025 came in at just 71% - a 23-point swing worth factoring into travel timing.

On the multi-year calendar, SEA–BLI peaks in October at 89.6% on-time while July carries the heaviest traffic (~115 flights per month) ; the softest month is June at 80.0%, a 9.6-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does SEA to BLI rank among US routes by traffic?
According to PlainFlights' route traffic ranking, SEA to BLI ranks #2089 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 BLI?
Flights from Seattle to Bellingham have a 85.1% on-time rate based on 5,958 flights. The average delay is 51.4 minutes. The best recent month was Dec 2024 with 94% on-time.
What is the cancellation rate for SEA to BLI?
Over the last 24 months, 1.4% of flights on this route were cancelled (32 of 2,325 flights) and 0.0% were diverted.
How far is the flight from SEA to BLI?
The flight distance from Seattle (SEA) to Bellingham (BLI) is approximately 93 miles. This route is served by 2 carriers.
When is the best time to fly from SEA to BLI?
The best recent month for on-time performance was Dec 2024 (94% on-time). The worst was Jun 2025 (71% on-time). Consider booking during months with historically better performance.

Airports on this route

Data source

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

Using SEA–BLI data

SEA–BLI runs 6.1 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 BLI airport profiles: delay causes and top routes differ even on the same corridor. SEA airport
  • If your dates flex, October (89.6% on-time) beats June (80.0%) on this corridor. Seasonal chart
  • 4 other routes post a similar 85.1% 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.