ON TIMEBOARD

SEA → BLI on time

Seattle-Tacoma (Seattle, WA) to Bellingham (Bellingham, WA). Every scheduled flight, September 2025 to August 2026.

On time
82%
arrived < 15 min late
Cancelled
2.3%
1,213 flights
Typical arrival
−6 min
median vs schedule
When late
+53 min
average delay
Flights / day
3
1 airline

82% of flights from Seattle to Bellingham arrived on time over the past 12 months. That is about the typical U.S. route. The 8 p.m. departures ran on time 92% of the time; the noon ones 75%. 7% of flights arrived more than an hour late or not at all.

How late?

The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for SEA → BLI: when a flight was late, it was under 45 minutes late 60% of the time. About 1 in 22 flights landed an hour or more late, and 1 in 243 three hours or more; 2.3% were cancelled outright.

Share of all 1,213 scheduled flights, past 12 months, by arrival time against schedule.

By airline

AirlineFlightsOn timeCancelledTypical arrival1h+ lateAvg when lateOperated by
Alaska Airlines1,21382%2.3%−6 min4.5%+53 minSkyWest 98%, Horizon Air 2%

Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.

Best time of day to fly

On-time rate by scheduled departure hour (local time at SEA). Delays build through the day as late planes knock on, so early flights usually do best.

40%70%100%10 a.m. departures: too few flights (34 flights)10a11 a.m. departures: 79% on time (219 flights)7911anoon departures: 75% on time (111 flights)7512p1 p.m. departures: too few flights1p2 p.m. departures: 77% on time (141 flights)772p3 p.m. departures: too few flights (86 flights)3p4 p.m. departures: too few flights (63 flights)4p5 p.m. departures: too few flights (34 flights)5p6 p.m. departures: too few flights6p7 p.m. departures: too few flights7p8 p.m. departures: 92% on time (115 flights)928p9 p.m. departures: too few flights (46 flights)9p10 p.m. departures: too few flights10p11 p.m. departures: 87% on time (364 flights)8711p
SEA → BLI, share of flights arriving on time, by departure hour. Hours with under 100 flights are greyed out.
82%+ on time76–82%68–76%under 68%too few flights

Last flight of the day

On SEA → BLI, each airline's last flight of the day was cancelled 3.0% of the time, against 2.0% for its earlier flights (1.5× as often). It arrived 3+ hours late 0.0% of the time (earlier flights: 0.6%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.

AirlineLast departureLast: cancelledLast: 3h+ lateEarlier: cancelledNext morning
Alaska Airlines11:01 p.m.3.0%0.0%2.0%first flight 12:05 p.m.

Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.

If you need to be in BLI tonight, book an earlier flight so there's a backup if it's cancelled.

By month

Each calendar month pooled over 2023–2026. Best: April (87%). Worst: August (72%).

40%70%100%Jan: 82% on time (273 flights)82JanFeb: 81% on time (244 flights)81FebMar: 81% on time (273 flights)81MarApr: 87% on time (269 flights)87AprMay: 84% on time (295 flights)84MayJun: 76% on time (294 flights)76JunJul: 81% on time (305 flights)81JulAug: 72% on time (305 flights)72AugSep: 80% on time (265 flights)80SepOct: 86% on time (274 flights)86OctNov: 84% on time (259 flights)84NovDec: 81% on time (268 flights)81Dec

By day of week

DayFlightsOn timeCancelled
Monday17883%1.1%
Tuesday17584%2.3%
Wednesday17384%4.0%
Thursday17180%1.2%
Friday17375%2.3%
Saturday17484%3.5%
Sunday16982%1.8%

Why flights were late

Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.

Late inbound plane 53%Airline (crew, maintenance, ops) 26%Air traffic & airport (NAS) 17%Severe weather 4%

Cancellations: weather 14 · air traffic/airport 11 · airline 3

Month by month

60%80%100%Sep 2023Jan 2024Jan 2025Jan 2026Jan 2025: 81% on time, 4.4% cancelledFeb 2025: 69% on time, 2.9% cancelledMar 2025: 73% on time, 1.0% cancelledMay 2025: 79% on time, 0.0% cancelledJun 2025: 71% on time, 0.0% cancelledJul 2025: 81% on time, 0.8% cancelledAug 2025: 81% on time, 0.8% cancelledSep 2025: 85% on time, 0.0% cancelledOct 2025: 85% on time, 1.6% cancelledNov 2025: 79% on time, 9.4% cancelledDec 2025: 74% on time, 2.4% cancelled
Share of flights on time, by month (hover a point for cancellations)
SEA → BLI, monthly on-time and cancellation rate.

Flight numbers on this route

Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.

FlightDepartsFlightsOn timeCancelledTypical arrivalOperated by
AS 329412:05 p.m.29877%2.7%−4 minSkyWest
AS 34333:50 p.m.25879%2.3%−4 minSkyWest
AS 346011:10 p.m.26988%3.4%−10 minSkyWest

Worst days in the past year

DateFlightsOn timeCancelled
Dec 12, 202540%0
Jan 18, 202630%2
Aug 24, 202630%0
Mar 13, 202630%2
Aug 7, 202630%0

Questions

How often are flights from SEA to BLI on time?

82% of 1,213 scheduled flights from Seattle, WA to Bellingham, WA arrived within 15 minutes of schedule between September 2025 and August 2026. 2.3% were cancelled.

What is the best time of day to fly SEA to BLI?

Flights scheduled to leave at 8 p.m. were the most reliable (92% on time). The noon departures were the least (75%).

What month has the most delays from SEA to BLI?

August (72% on time). The best month is April (87%), over 2023–2026.

Is the last flight of the day from SEA to BLI more likely to be cancelled?

Yes. Each airline's last SEA–BLI flight of the day was cancelled 3.0% of the time over the past year, against 2.0% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.

Related

Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.