Route reliability record
BLI→SEA
Bellingham to Seattle
- Flights
- 1,186
- Period
- September 2025 to August 2026
- Distance
- 93 mi
- Carriers
- 1
This route lands a B, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That rests on 1,186 BLI to SEA flights, with a median arrival 4 minutes early.
Best time to fly BLI to SEA: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 90.4% of the time and Saturday flights 87.3%, against 81.1% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.1%
Arrivals under 15 minutes late, of 1,160 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
2.11%
National rate is 1.89%
Best carrier
SkyWest
81.1% on time across 1,186 flights
These figures cover 1,186 flights between September 2025 and August 2026. The median arrival is 4 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.
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Carrier by carrier
Which airline is most reliable on BLI to SEA
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 | 1,186 | 81.1% | 54 min | 2.11% | B |
Flight by flight
Flights on BLI to SEA
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.
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Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against half a point between the best and worst carrier.
- 5am–8am363 flights90.4%
- 8am–11am135 flights82.7%
- 11am–2pm324 flights76.8%
- 2pm–5pm182 flights71.8%
- 5pm–8pm182 flights78.5%
- 8pm–5am—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.4% of the time, against 71.8% for the afternoon window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 363 flights scheduled in it.
Explore
Filter BLI to SEA 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 BLI to SEA, the best departure window is 5am–8am at 90.4% on time and the worst is 2pm–5pm at 71.8%, a wide gap of 18.6 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am90.4%
- 8–11am82.7%
- 11am–2pm76.8%
- 2–5pm71.8%
- 5–8pm78.5%
- 8pm–5am—
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 30 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 61.3% on time, 30 points below April, the best at 91.1%. 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, Saturday is the strongest day at 87.3% on time and Friday the weakest at 72.7%, a spread of 15 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 12,000 reported delay minutes.
- 41%Late-arriving aircraft
- 36%Carrier
- 16%National Airspace System
- 8%Extreme weather
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 12,000 reported delay minutes here, that single category outweighs weather by 5 to one. The split is drawn from 11,837 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,209 of the 12,000 delay minutes reported here.
Cancellations sit at 2.11% against a national 1.89%, which is ordinary. Diversions add another 0.08%.
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 5am–8am window matters as much as it does.
The return leg runs 83.3% on time across 1,185 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 1,186 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 SEA 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 91.1% on time and August 61.3%, a swing of 30 points. If the dates move at all, move them out of August before you think about anything else. 1,160 completed flights over 12 months sit behind that.
Common questions
BLI to SEA questions
How often is BLI to SEA delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.9% of the 1,186 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 55 minutes on average.
How reliable is BLI to SEA compared with the rest of the country?
81.1% of flights arrive on time here against a national 77.3%, a difference of 4 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on BLI to SEA?
The 5am–8am departure window is the strongest at 90.4% on time. The 2pm–5pm window is the weakest at 71.8%, 19 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 BLI to SEA?
August is the weakest month at 61.3% on time, compared with 91.1% in April. Across the year that is 30 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
- SEA to BLI — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- LAX to SEA, a related route85.0%
- PHX to SEA, a related route82.2%
- SFO to SEA, a related route72.3%
- SkyWest Airlines on-time record81.1%
- 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. BLI to SEA and SEA to BLI are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.