Route reliability record
SEA→BLI
Seattle to Bellingham
- Flights
- 1,185
- Period
- September 2025 to August 2026
- Distance
- 93 mi
- Carriers
- 1
This route lands a B, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That rests on 1,185 SEA to BLI flights, with a median arrival 6 minutes early.
Best time to fly SEA to BLI: a 8pm–5am departure, ideally on a Wednesday. Flights in that window arrived on time 88.4% of the time and Wednesday flights 87.7%, against 83.3% for the route overall.
Set against the rest of the country, this route's record is 6 points better than the US average of 77.3%. That gap is worth roughly 60 fewer late arrivals for every thousand flights.
Key figures
On time
83.3%
Arrivals under 15 minutes late, of 1,158 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
2.28%
National rate is 1.89%
Best carrier
SkyWest
83.3% on time across 1,185 flights
These figures cover 1,185 flights between September 2025 and August 2026. The median arrival is 6 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Which airline is most reliable on SEA to BLI
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 1,185 | 83.3% | 53 min | 2.28% | B |
Flight by flight
Flights on SEA to BLI
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,185 flights.
- 5am–8am—
- 8am–11am34 flights84.8%
- 11am–2pm330 flights79.6%
- 2pm–5pm290 flights78.5%
- 5pm–8pm34 flights85.3%
- 8pm–5am497 flights88.4%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
The overnight block holds up unusually well at 88.4% on time across 497 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 497 flights scheduled in it.
Explore
Filter SEA to BLI by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SEA to BLI, the best departure window is 8pm–5am at 88.4% on time and the worst is 2pm–5pm at 78.5%, a real gap of 9.9 points. All US flights leaving 8pm–5am ran 70.1%.
- 5–8am—
- 8–11am84.8%
- 11am–2pm79.6%
- 2–5pm78.5%
- 5–8pm85.3%
- 8pm–5am88.4%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 34 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 59.1% on time, 34 points below April, the best at 93.3%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. December was the busiest month here, with 124 flights.
Across the week, Wednesday is the strongest day at 87.7% on time and Friday the weakest at 75.9%, a spread of 12 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 53% of the 10,000 delay minutes carriers reported here, and the remaining four split what is left.
- 53%Late-arriving aircraft
- 26%Carrier
- 17%National Airspace System
- 4%Extreme weather
53% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 10,000 reported delay minutes here, that single category outweighs weather by 13 to one. The split is drawn from 10,189 reported delay minutes.
Cancellations sit at 2.28% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.8% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 93 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8pm–5am window matters as much as it does.
The return leg runs 81.1% on time across 1,186 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,185 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in BLI after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 93.3% on time and August 59.1%, a swing of 34 points. If the dates move at all, move them out of August before you think about anything else. 1,158 completed flights over 12 months sit behind that.
Common questions
SEA to BLI questions
How often is SEA to BLI delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.7% of the 1,185 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 55 minutes on average.
How reliable is SEA to BLI compared with the rest of the country?
83.3% of flights arrive on time here against a national 77.3%, a difference of 6 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on SEA to BLI?
The 8pm–5am departure window is the strongest at 88.4% on time. The 2pm–5pm window is the weakest at 78.5%, 10 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are August delays on SEA to BLI?
August is the weakest month at 59.1% on time, compared with 93.3% in April. Across the year that is 34 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BLI to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- SEA to LAX, a related route82.0%
- SEA to PHX, a related route78.2%
- SEA to SFO, a related route59.8%
- SkyWest Airlines on-time record83.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. SEA to BLI and BLI to SEA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed SEA to BLI’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.